Using 3.6.0a, I have experienced the same chunk generation problems as issue #91 . The mediafire link to its solution has expired. Can the fix be incorporated into the next release, and/or can the file that was available for download be re-uploaded?

Please use our forum thread to report errors. This is mainly used for development issues/ideas. =)
You should probably get version 3.7.0a which is also for 1.4.5 and the 2 updates since 3.6.0 fixed several bugs. The link to it is on the OP of the forum thread and the Change log can be found here:
https://github.com/ExtrabiomesXL/ExtrabiomesXL/wiki/Change-Log

The problem in #91 was a bug in ForgeModLoader, which was fixed. That problem no longer exists. Similar world tearing can occur when biomes are disabled or enabled after world creation, or when mods are added that add biomes. This is not a problem with Extrabioes, this is a result of how Minecraft generated terrain.