Why do I get Your network admin prevented access to '?', please move onto next step.

I have a multisite install and the whole network belongs to one customer.
They have a forum on one subsite, a directory on 2 others and their main site is the root. I currently use snapsitemap for generating our sitemap but we have exceeded 10k pages and the next cost bracket is a bit steep. I thought I would have a look at sitemap plugins again. The problem I'm finding is they either aren't multisite compatible or they don't pick up the dynamic forum pages made by simplepress. I am trying Infinate SEO but am getting the error in this topic title. Look forward to any help you can offer.