"Winbspc" is a map "de-compiler", not a compiler...
As far as map compilers go I prefer LordHavoc's lmap2, most current release here:
http://icculus.org/twilight/darkplaces/ ... 3beta1.zip
Read the README and try that to see it works for you...
..also:
..The whole "..The process cannot access the file because it is being used by another process.." thing a lot of times indicates the file is locked by another process. So if Worldcraft or any program has your map file open, then close them and compile from either the command line or use batch files...