Yes, I normally do the same. I am always working in english language OSes, even at home. But in this case - it's my main MOSS development VM - I installed because I had to create a demoable site in german language and at that time I didn't know about the language packs. All our servers are in english.
But that doesn't help me with this error... Do I have a chance to remove and reinstall MOSS EN without much trouble
Or maybe you know something about the cause for my problem: I changed the web part filter sample to send other data and connected it to the list view webpart. The list view webpart then gives the message, sounding something like 'Too much data sent to the web part. Please disconnect some webparts and try again.' in english. The message is misleading, there is only one web part connected. That web part only sends one name/value pair and works fine in connection with one of the other sample web part comsumers.