How to backup RHLE 5.3 32bit on 7.6.0.4 platform

HI all ，here is my problem

the master/media server is win2008r2 64bit 

netbackup:7.6.0.4

there is a client ,RHLE 5.3 32bit.

as i know ,32bit RHLE  no longer be support now.

which release client should i use for this client?

I try to install netbackup 6.5 client for linux on this host, but the master retuen "socket write failed" when i configure the client.