I agree with Marshall, you need to have the code for num2Pstring fixed, this is very broken. Besides, it seems to be a bad reinvention of the sprintf function.

The source of util.c is on the same web server (simply tried it, seems to work).

After that, compiling the program is by far the easiest option and that is not very difficult if you know how.

Converting this program to Perl is not going to change anything: the c-program works as a CGI program (I can see that from the code), for which the web server has to be configured by the sysadmin. If you have your program converted to Perl, you would still have to run it as a CGI program (there are different options, but those are waaay more difficult).