How to change the server name

Hello,

Coming to the end of the testing phase and I have a server instance MySrv
that runs jobs also called MySrv.
So I asked for our own administrator to create 2 new instances, PROD and
TEST. I thought I could just replace the httpd.conf files of the new
servers with that of MySrv and then modify them to fit the IFS folders.
I've done this with the new server TEST but when attempting an http request
I'm getting the following error :

ZSRV_MSG0107: Premature end of script headers: File name is MyPgm.pgm

The message must relate to the line :
ScriptAlias /MyURL /qsys.lib/ MyLib.lib/ MyPgm.pgm
As this is the only reference to MyPgm in the script.

I'm guessing there might just be an easier way to change the server name
and hopefully one of you will know how to do that or will understand the
error message.

Thanks!