On my live forum.
http://www.wikiwirral.co.uk/forums/ubbthreads.php/topics/984942/106-to-112-bentinck-street-help-photos.html#Post984942
...the original via my mobile when clicking on it eventually throws this at me
http://192.168.250.1/infoThe recent post island and New Topic island and the topic subject pull the same extra long broken url.
It looks like the hotel's wifi connection to the outside network (internet) had a hiccup or just timed-out.
Your error could have happened to any other internet website at that exact time.
Just feed back, incase there is an issue with / in the subject line.
From the URL you've posted, it doesnt look like the topic's "slash" had anything to do with the problem you had. The topic's "slash" didnt even make it in to the url.
The sixth line of sanitization code in the OP says: Convert anything that is not an A-z, a-z, 0-9 character (ie, "A-Za-z0-9") to a dash. It basically sanitizes the whole topic, for inclusion in to the URL.