This is Cecil's spiffy web-listening machine. It is useful for debugging things.

Error encountered; please report this error to a wizard.

Error was: E_PROPNF (Property not found); value: 0

VerbLoc:VerbProgrammerThisPlayerLine
#1343:tell_www_page #7407#1343#76106
#80:serve_page #789#80#761042
#81:do_GET #55#7610#761012
#81:do_null_command #55#7610#76109
#80:do_null_command #789#80#76101

You can cut-and-paste the following:

#1343:tell_www_page (this == #1343), line 6: Property not found
... called from #80:serve_page (this == #80), line 42
... called from #81:do_GET (this == #7610), line 12
... called from #81:do_null_command (this == #7610), line 9
... called from #80:do_null_command (this == #80), line 1
(end of traceback)