downgrading Gcc

[Leon Collis]

We are having some problems compiling code for a 
customized version of OpenDx. The creator is recommending 
I use an older compiler (Gcc 3.4) rather than 4.0.0 that 
is currently installed on my system. Installation of this 
software works ok on his system (that uses Gcc 3.4). Is 
there a relatively easy process to downgrading to 3.4, 
i.e. downloading a set of *.rpm files? After searching 
online it appears as though you can run into trouble with 
libraries etc.

Any help will be much appreciated.

Sincerely,

Leon Collis