MySQLDump through PHP/HTML UI

Hello - - -- -

I have a utility which creates a MySQLDump of selected tables or the  
whole database.  This works fine on my development machine, a W2K  
box. It does not work on the testing server, a linux box.

I'll post code if you want, but it is very simple:

1. I create the "dump" language, including the file into which the  
data is dumped into a variable.

2. I perform system($dump_language). I also tried it exec 
($dump_language). Both produce the same result:

The file is created (the directory is one for which the application  
has r/w rights). In Windoze, the file is complete and perfect. On the  
Linux box, only the header information of the dump file is written,  
nothing about any database or table.

Any ideas?

Thank you,

Ken