Windows7 and Modelsim 6.5e

I know its not officially supported but I'm trying/hoping to use Modelsim Altera on Windows7.

This is a full license running off a USB dongle.

Quartus works fine.

Things seem ok on Modelsim - simulates OK, but after a while it complains about loosing the license. The only way to be able to continue is to restart modelsim.

Anyone had similar issue?