Problem when running Form from Builder

My preference setting for runtime is: http://localhost:9001/forms/frmservlet - and it works w/o a problem.

If I run a form AND it has an error and I have to kill the browser (IE 9) to terminate because "EXIT_FORM" does not work, then the next time I want to run the form from Builder

I get the following in the browser address: http://localhost:50375/XgAYSBltUBTjubpy6gwmrjIOLM3wOzVcf3GRJKcF6iqQv2DM.

Of course this does not work! So my question is why is the browser's address scrambled/garbage and how do I get it to work again - it usually take 10 - 15 minutes till it works again.