In the TBC Classic Beta, version 4.10.7-4-g51f247e-bc posts an error:

9x Error loading Bartender4\libs\LibClassicSpellActionCount-1.0\LibClassicSpellActionCount-1.0.lua

This library appears missing from the build. If I copy this library from the Classic version (which is present), then it doesn't post this error anymore. Not sure if the library is used in the BC version, but it's still seems to reference it.