Hi,
I have had similar problems in the past (not with the 7.1 installer) and it may be worth trying this:
Found that the database could not be configured because smaller solutions were not installed (like SEP connector etc.), but I could not install them at same time as CMS. Found this worked:
- Installed CMS with a new database
- Once installation is complete install additional components you may have had (SEP Connect, Servicedesk etc.)
- Go into database settings and point server to old database. The configur procedure should now run through without an error.
Hope this helps.