Ok. Here is the error message:
Request Error
There appears to be a programming bug in ad_parse_html_attributes_upvar: We've entered an infinite loop.
while executing
"error "There appears to be a programming bug in ad_parse_html_attributes_upvar: We've entered an infinite loop.""
(procedure "ad_parse_html_attributes_upvar" line 17)
Apparently, when the ad_parse_html_attributes proc hits a long code block inside <pre> tags it bombs out.