When I log in, I get four errors, use 8.0.2-Beta1 version.
<1>：
1x OmniCC_Config\panels\general-綜合.lua:284: attempt to index upvalue 'Cooldown' (a nil value) OmniCC_Config\panels\general-綜合.lua:284: in function SetSavedValue'
OmniCC_Config\widgets\slider.lua:54: in function <OmniCC_Config\widgets\slider.lua:49>
[C]: in function SetValue' OmniCC_Config\widgets\slider.lua:95: in function UpdateValue'
OmniCC_Config\panels\general-綜合.lua:66: in function UpdateValues' OmniCC_Config\panels\general-綜合.lua:338: in main chunk [C]: ? [C]: in function LoadAddOn'
OmniCC\main.lua:14: in function <OmniCC\main.lua:13>
[C]: in function Show' FrameXML\UIParent.lua:2614: in function SetUIPanel'
FrameXML\UIParent.lua:2420: in function ShowUIPanel' FrameXML\UIParent.lua:2320: in function <FrameXML\UIParent.lua:2316> [C]: in function SetAttribute'
FrameXML\UIParent.lua:3141: in function ShowUIPanel' Oilvl\Oilvl-v8.0.1 BFA Alpha.lua:5545: in function ?'
Oilvl\Oilvl-v8.0.1 BFA Alpha.lua:5692: in function <Oilvl\Oilvl.lua:5691>

Locals:
self = OmniCCOptions_GeneralSpiral transparency {
0 =
type = 3
High = OmniCCOptions_GeneralSpiral transparencyHigh {
}
Low = OmniCCOptions_GeneralSpiral transparencyLow {
}
GetSavedValue = defined @OmniCC_Config\panels\general.lua:287
tooltip = "Sets the opacity of the dark spirals you normally
see on buttons when on cooldown."
Thumb = OmniCCOptions_GeneralSpiral transparencyThumb {
}
Text = OmniCCOptions_GeneralSpiral transparencyText {
}
SetSavedValue = defined @OmniCC_Config\panels\general.lua:282
GetFormattedText = defined @OmniCC_Config\panels\general.lua:291
valText = {
}
}
value = 1.0099999774247
(*temporary) = nil
(*temporary) = nil
(*temporary) = "base"
(*temporary) = "attempt to index upvalue 'Cooldown' (a nil value)"
parent = OmniCCOptions_General {
CreateMinSizeSlider = defined @OmniCC_Config\panels\general.lua:182
AddWidgets = defined @OmniCC_Config\panels\general.lua:18
UpdateValues = defined @OmniCC_Config\panels\general.lua:57
NewSlider = defined @OmniCC_Config\panels\general.lua:152
CreateSpiralOpacitySlider = defined @OmniCC_Config\panels\general.lua:278
CreateScaleTextCheckbox = defined @OmniCC_Config\panels\general.lua:112
CreateMinDurationSlider = defined @OmniCC_Config\panels\general.lua:161
CreateMinEffectDurationSlider = defined @OmniCC_Config\panels\general.lua:200
CreateTenthsSlider = defined @OmniCC_Config\panels\general.lua:253
buttons =

<2>：
1x OmniCC_Config\panels\general-綜合.lua:231: attempt to call method 'ForAll' (a nil value) OmniCC_Config\panels\general-綜合.lua:231: in function SetSavedValue'
OmniCC_Config\widgets\slider.lua:54: in function <OmniCC_Config\widgets\slider.lua:49>
[C]: in function SetValue' OmniCC_Config\widgets\slider.lua:95: in function UpdateValue'
OmniCC_Config\panels\general-綜合.lua:66: in function UpdateValues' OmniCC_Config\panels\general-綜合.lua:338: in main chunk [C]: ? [C]: in function LoadAddOn'
OmniCC\main.lua:14: in function <OmniCC\main.lua:13>
[C]: in function Show' FrameXML\UIParent.lua:2614: in function SetUIPanel'
FrameXML\UIParent.lua:2420: in function ShowUIPanel' FrameXML\UIParent.lua:2320: in function <FrameXML\UIParent.lua:2316> [C]: in function SetAttribute'
FrameXML\UIParent.lua:3141: in function ShowUIPanel' Oilvl\Oilvl-v8.0.1 BFA Alpha.lua:5545: in function ?'
Oilvl\Oilvl-v8.0.1 BFA Alpha.lua:5692: in function <Oilvl\Oilvl.lua:5691>

Locals:
self = OmniCCOptions_GeneralMinimum duration to display text as MM:SS {
0 =
type = 3
High = OmniCCOptions_GeneralMinimum duration to display text as MM:SSHigh {
}
Low = OmniCCOptions_GeneralMinimum duration to display text as MM:SSLow {
}
GetSavedValue = defined @OmniCC_Config\panels\general.lua:234
tooltip = "Determines the threshold
for showing a cooldown
in a MM:SS format."
Thumb = OmniCCOptions_GeneralMinimum duration to display text as MM:SSThumb {
}
Text = OmniCCOptions_GeneralMinimum duration to display text as MM:SSText {
}
SetSavedValue = defined @OmniCC_Config\panels\general.lua:225
GetFormattedText = defined @OmniCC_Config\panels\general.lua:241
valText = {
}
}
value = 1
(*temporary) = nil
(*temporary) =

<3>：
1x OmniCC_Config\panels\general-綜合.lua:259: attempt to call method 'ForAll' (a nil value) OmniCC_Config\panels\general-綜合.lua:259: in function SetSavedValue'
OmniCC_Config\widgets\slider.lua:54: in function <OmniCC_Config\widgets\slider.lua:49>
[C]: in function SetValue' OmniCC_Config\widgets\slider.lua:95: in function UpdateValue'
OmniCC_Config\panels\general-綜合.lua:66: in function UpdateValues' OmniCC_Config\panels\general-綜合.lua:338: in main chunk [C]: ? [C]: in function LoadAddOn'
OmniCC\main.lua:14: in function <OmniCC\main.lua:13>
[C]: in function Show' FrameXML\UIParent.lua:2614: in function SetUIPanel'
FrameXML\UIParent.lua:2420: in function ShowUIPanel' FrameXML\UIParent.lua:2320: in function <FrameXML\UIParent.lua:2316> [C]: in function SetAttribute'
FrameXML\UIParent.lua:3141: in function ShowUIPanel' Oilvl\Oilvl-v8.0.1 BFA Alpha.lua:5545: in function ?'
Oilvl\Oilvl-v8.0.1 BFA Alpha.lua:5692: in function <Oilvl\Oilvl.lua:5691>

Locals:
self = OmniCCOptions_GeneralMinimum duration to display tenths of seconds {
0 =
type = 3
High = OmniCCOptions_GeneralMinimum duration to display tenths of secondsHigh {
}
Low = OmniCCOptions_GeneralMinimum duration to display tenths of secondsLow {
}
GetSavedValue = defined @OmniCC_Config\panels\general.lua:262
tooltip = "Determines the threshold
for showing tenths of seconds."
Thumb = OmniCCOptions_GeneralMinimum duration to display tenths of secondsThumb {
}
Text = OmniCCOptions_GeneralMinimum duration to display tenths of secondsText {
}
SetSavedValue = defined @OmniCC_Config\panels\general.lua:257
GetFormattedText = defined @OmniCC_Config\panels\general.lua:266
valText = {
}
}
value = 0
(*temporary) = nil
(*temporary) =

<4>：
1x OmniCC_Config\panels\general-綜合.lua:188: attempt to call method 'ForAll' (a nil value) OmniCC_Config\panels\general-綜合.lua:188: in function SetSavedValue'
OmniCC_Config\widgets\slider.lua:54: in function <OmniCC_Config\widgets\slider.lua:49>
[C]: in function SetValue' OmniCC_Config\widgets\slider.lua:95: in function UpdateValue'
OmniCC_Config\panels\general-綜合.lua:66: in function UpdateValues' OmniCC_Config\panels\general-綜合.lua:338: in main chunk [C]: ? [C]: in function LoadAddOn'
OmniCC\main.lua:14: in function <OmniCC\main.lua:13>
[C]: in function Show' FrameXML\UIParent.lua:2614: in function SetUIPanel'
FrameXML\UIParent.lua:2420: in function ShowUIPanel' FrameXML\UIParent.lua:2320: in function <FrameXML\UIParent.lua:2316> [C]: in function SetAttribute'
FrameXML\UIParent.lua:3141: in function ShowUIPanel' Oilvl\Oilvl-v8.0.1 BFA Alpha.lua:5545: in function ?'
Oilvl\Oilvl-v8.0.1 BFA Alpha.lua:5692: in function <Oilvl\Oilvl.lua:5691>

Locals:
self = OmniCCOptions_GeneralMinimum size to display text {
0 =
type = 3
High = OmniCCOptions_GeneralMinimum size to display textHigh {
}
Low = OmniCCOptions_GeneralMinimum size to display textLow {
}
GetSavedValue = defined @OmniCC_Config\panels\general.lua:191
Thumb = OmniCCOptions_GeneralMinimum size to display textThumb {
}
tooltip = "Determines how big a frame must be to display text.
The smaller the value, smaller things can be to show text.
The larger the value, the bigger things must be.

Some benchmarks:
100 - The size of an action button
80 - The size of a class or pet action button
55 - The size of a target frame buff"
SetSavedValue = defined @OmniCC_Config\panels\general.lua:186
Text = OmniCCOptions_GeneralMinimum size to display textText {
}
valText = {
}
}
value = 50
(*temporary) = nil
(*temporary) =

Did you remove both OmniCC folders from your addons directory before installing?