Is my rim too thin?

Hmm, I tried all this. Didn't work.

I will bring the wheel to one of the drinks for confirmation of one of the following

a) I am too stupid to put a tire in.
b) This rim/valve combination is somehow funky.

Cheers for the quick responses.
If a, which seems to be the odds on favourite with bookmakers at the moment, then do you really want to turn up at drinks and have it confirmed in front of a captive audience? It sounds like the tyre hasn't seated on the rim properly. Have you tried pushing the valve back into the tyre, which should seat the tyre? Also read through this;

http://www.parktool.com/repair/readhowto.asp?id=100