The page you linked doesn’t seem to have any maps or mashups, and the only resource being loaded by MapPress is a small CSS file (‘mappress.css’).
It seems like delay is on the server itself. It’s taking about 7 seconds to respond initially and again when this resource is loaded:
One possible cause is the server is running out of memory. When this happens, activating another plugin can cause push you over the memory limit. See the FAQ for some suggestions about adjusting memory limits.
Another possibility is PHP or Apache errors during the page requests. You can check the server PHP and Apache error logs to see if that’s happening.
Here are some steps additional steps to troubleshoot the problem:
1. Switch to a standard theme
2. Deactivate ALL other plugins except MapPress
If that fixes the issue, reactivate one by one to find the problem. If not, you can send me a login (you can use the contact form on this site) and I’ll take a look from the admin screens.