Oh grief, I misinterpreted the error to be the result of the "$<" operation. The actual problem is the fact that my now lesser-privileged user is not authorised to perform the next "$< = $> = $newid" iteration.

Hmm, my question should actually read: "How do I perform seteid()" or "How do I temporarily drop my privileges before calling a function? ". The obvious answer is $>. *hides in shame*

-0xbeef