Indeed size is a big part of the problem. 10 GB is big, even after zipping it up. And I already spent 24 hours(!) uploading that Beta 2.1 installer. 
If you have an Intel GFX card, the game won't run until after the Beta 2.5 installation, which is quite annoying.
Get around that by installing this first: http://www.moddb.com/mods/potc-build-mod/downloads/intel-graphics-fix
If Windows Security Stupidity is messing things up, try installing on another computer -ANY computer- and putting the results on an external HD to transfer it to your own one.

If you have an Intel GFX card, the game won't run until after the Beta 2.5 installation, which is quite annoying.
Get around that by installing this first: http://www.moddb.com/mods/potc-build-mod/downloads/intel-graphics-fix
If Windows Security Stupidity is messing things up, try installing on another computer -ANY computer- and putting the results on an external HD to transfer it to your own one.