UBB.threads PHP Forum Software Community Forums UBB.threads Version 7/8 Support Can UBB cause resources problems?

Hello

I have a two part question. Firstly I am running version 7.1 and recently my VPS has started crashing constantly. I was told by the hosting company that my site is too memory intensive as they are getting the message:
ash-3.00# grep -ri memory /var/log/httpd/error_log
[error] (12)Cannot allocate memory: fork: Unable to fork new process

Could the UBB forum be using up all the resources? It is the only thing I have running and I am not sure if it could be the source of my problems.

My second question is if I move to a new server running php 5 and MySQL5, would there be any incompatibilities or should UBB 7.1 work fine?

I am not very technical so your help will be appreciated

Thanks