I switched to using SuExec on a new machine, and it seems to refuse to execute scripts which have +rw set for the group, eventually spitting out the error message in the form of "Premature end of script headers".

Yeah, as I already said here when transferring my blog, this was pretty non-obvious to find out, especially so since most people tend to look for Pyblosxom problem, instead of SuExec.

Though, Data might be having entirely different problem, but since there are some security consious comments there, I guess SuExec is used as well :)