hi Sam, I would suggest that win7 is actually protecting you in not letting MxM start WinMx, as this could be seen as malware behaviour. It could depend on what folders the programs are installed to as some folders have more protection that others. Of course it might not be that at all, and you'll have to put up with the extra click. Does MxM work normally after both programs are started? if not then maybe the path to winmx set in MxM is incorrect.
As to the timing out, check the TCP port in a webpage port tester to see if it is open (Winmx needs to be running when u check this). If this test says port closed then thats where the issue is currently. Might be you need to specifically allow these ports through the win7 firewall. Try firewall off momentarily when doing the port test to test this.