Change language of system (to none english) - i'll add my .mo file to this bug that you be able to check
On admin panel go to Products
try to choice from combo Edit option (i didn't finish translation so you will see Edit in english and Product as hebrew characters)
click on GO (hebrew characters)

result: no page is loaded.
In adress i can see that you build some attribute "do" from combo value - so it looks like one word on English and one Hebrew. If i change hebrew word to product (result: editproduct) page loaded.

Thank you for your bug report. This issue has been closed and fixed in Subversion. This change will be available in a future release, but you can download the change at any time from the Subversion server.

Here's the fix for this bug.