Traffic from ip address xxx.xxx.xxx.xxx is blocked

Dear Sir/Madam,

I have recently created two clean workstation images on our network and I am receiving 'traffic from ip address xxx.xxx.xxx.xxx is blocked...' messages.

The ip addresses are those within our network range.  They only appear on the two workstations that we have created and not on any of the many other established networked workstations.

I have read some of the boards here but cannot figure out how to resolve the issue.

I just want to make sure we haven't got a serious problem.  Our SEP software is up to date, as are the workstations,

What would I need to do to prevent the messages from appearing without stopping the SEP from doing its job?

Any help would be greatly appreciated.