This applies to Linux hosting accounts only.

If the program is a CGI binary written in a language such as C it may not run if the program was compiled on a different platform such as s Sun Solaris machine.

It will need to be compiled on a 0x86 Linux platform.

If the CGI is written in a scripting language such as ASP, PHP or Perl then make sure it has the correct interpreter line at the start of the script and the file permission are set to '755' (other articles in the CGI section cover this).