When i try to create a (Default world type) world, it reaches a point when the game freezes, without any text in the screen, just the dirt blocks background.

I looked in the logs searching for any hint, then i found this, that says to me report it. So, i'm reporting:

[22:24:42] [Server thread/WARN] [FML]: Quark loaded a new chunk [-25, 19] in dimension 0 (overworld) while populating chunk [-24, 19], causing cascading worldgen lag.
[22:24:42] [Server thread/WARN] [FML]: Please report this to the mod's issue tracker. This log can be disabled in the Forge config.
[22:24:42] [Server thread/WARN] [FML]: Quark loaded a new chunk [-26, 19] in dimension 0 (overworld) while populating chunk [-24, 19], causing cascading worldgen lag.
[22:24:42] [Server thread/WARN] [FML]: Please report this to the mod's issue tracker. This log can be disabled in the Forge config.
[22:24:42] [Server thread/WARN] [FML]: Quark loaded a new chunk [-27, 19] in dimension 0 (overworld) while populating chunk [-24, 19], causing cascading worldgen lag.
[22:24:42] [Server thread/WARN] [FML]: Please report this to the mod's issue tracker. This log can be disabled in the Forge config.

(This is the part of the logs that talks about a Quark error)

Later on the logs i've found a part that says what is the fatal error, and isn't Quark's fault

The part you included is normal, it'll happen when quark generates some larger structures.