Also try searching the forum for keywords relating to your problem. A lot of issues have already been discussed. For instance if you have problems with 'crypt' try searching for 'crypt'.
If that doesn't help, and you have problems compiling, please tell us:
Which version you are compiling (eg. ROM 2.4b6)
Which operating system and compiler you are using (eg. Linux, Windows with Cygwin, Windows with Visual C++)
If there is an error, an exact copy of the error message(s) - or a least the first 100. If you make a post saying 'I got an error' then we just have to reply asking what the error was, which wastes time.