SiteSeeker 4.2.91.1 upgrade, This operation is only valid on generic types

I upgraded SiteSeeker libraries from 4.2.89.1 to 4.2.91.1.

The site was using this type of solution to add a custom meta tag for UnifiedFile:
http://blogg.siteseeker.se/2012/06/27/anvand-siteseekers-indexeringsstod-for-filer-i-episerver/

After upgrade I got this error on startup: "This operation is only valid on generic types"

I solved it by using my own "siteseeker/fileinformation.aspx"-ish file but a bit annoying that things break without notes in the release log.

Still waiting for a call back from support...