Usually when I get a Sever Exception it means I just jacked up the syntax so bad it doesn't know what to tell me. I don't really know what's going on with yours, but the last time it gave me one of those I had this for my UI function:
FUNCTION MakeWindows()
aklghbaiga
gaiegu;hlae;g
aegaer;hrae
stuff
random
stuff
RETURN x$
Just keep looking for errors in your code, or if it's not too big put it in the source button and we'll take a look at it for you.
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