I think I noticed a bit of a problem with Mwebs Cache server and Minecraft, every time a new update rolls out for minecraft, mwebs cache server doesn't seem to update and sends the old files trough,resulting in a black screen when trying to play I know this because if I reconnect with with vodacom 3g and redownload the update it will work,until a new update is released, Ive compared both files with a hex editor and there very different,and other members of the minecraft community that's also mweb uncapped are experiencing the same thing.
PS Originally I started a thread about this on the minceraft forum
http://www.minecraftforum.net/viewtopic.php?f=17&t=66053 , if mweb can look into it, it would be great.
If your wondering what files are effected, heres a copy from java console: