I'm not sure how to force the value to populate the path info variable in IIS; if it was Linux there could be some troubleshooting options, but I don't end up finding too many fixes to IIS problems via searches.

As for URLs with "unallowed characters"; in attempting to fix a security issue with v7.5.8, the developer (at the time), introduced coding which allows characters that are not allowed in a URL (see RFC3986), and instead of following requests to update the coding accordingly it was just left as is (basically breaking URLs in some instances).

Id242 created a modification shortly after the release of v7.5.8 (available at: [7.5.8] Better URL Sanitization for SEO), which is what will be used in v7.6.0 (it is not in v7.5.9). Users utilizing the UBB.Sitemaps script should note that the latest build is capable of parsing the 7.6.0 URLs (changelog), but will not utilize the v7.5.8+ URLs as they don't follow specifications.

I am a Web Development Contractor, I do not work for UBBCentral. I have provided free User to User Support since the beginning of these support forums.
Do you need Forum Install or Upgrade Services?
Forums: A Gardeners Forum, Scouters World
UBB.threads: UBBWiki, UBB Styles, UBB.Sitemaps
Longtime Supporter & Resident Post-A-Holic
VNC Web Services: Code Modifications, Upgrades, Styling, Coding Services, Disaster Recovery, and more!