[otrs] A few agents get error "Magic number checking on storable string failed at ..\..\lib\Storable.pm"

This is specific to these (two) agents and follows them across browsers, computers, etc. The full exception is here (taken from PerlEx, though mod_perl does the same): Precompiler: Execute Error: Filename:[C:\OTRS\otrs-3.0.0\bin\cgi-bin\index.pl] Package:[PerlEx::Precompiler::c_::otrs::otrs2d3_0_0::bin::cgi2dbin::index_pl] Params[] Magic number checking on storable string failed at ..\..\lib\Storable.pm (autosplit into ..\..\lib\auto\Storable\thaw.al) line 415, at ../..//Kernel/System/Cache/FileStorable.pm line 128 PerlEx: Error return: -1 I assume this is a corrupt user preference, but I can't find one in the table that looks bad. Any suggestions? We're on OTRS 3.0.3. Hugh