Unhandled exception while browsing

[seanferns]

I was just trying out the new version 5.0. After visiting a webpage and then going to any other item in the data explorer pane I get an unhandled exception.
"An unhandled exception ("undefined' is null or not an object') occurred in UltraRecall.exe [2572]."
This occurs a few times and then I can continue working in UR.
I am using IE7 on Windows XP SP3. Is this supported or is moving to UR 5.0 conditioned on moving to IE9 ?