Thought others might benefit from my recent efforts with a Red Hat AS3.0 
client with NBU 5.0MP2.

Some clients installed fine and ran successfully on the first try, but 
another was a problem.  The client and server would "almost" talk to 
each other, but all attempts resulted in a status code of 25 or 58.  
Since most of our problems seem to be with firewalls lately, I wasted 
some time there, but to no avail.   The Veritas Troubleshooting Guide 
and a Knowledge-Base search helped not.

On a lark, I tried a telnet from the backup server to the client and 
received:

$ telnet xxx.yyy..maine.edu 13782
Trying 130.111.xxx.yyy...
Connected to xxx.yyy.maine.edu.
Escape character is '^]'.
bpcd: error while loading shared libraries: libstdc++-libc6.2-2.so.3: 
cannot open shared object file: No such file or directory
Connection to xxx.yyy.maine.edu closed by foreign host.

A look in the NetBackup 5.1 (!) Release notes showed the fix: install 
the compatibility library compat-libstdc++-7.3-2.96.122 (or later).

Hope this helps!    cheers, wayne