Went from RB v4.7 to v5 after the release since it seemed like it could be hugely beneficial but apparently Adobe released a very faulty and buggy piece of software. So uninstalling it and going back v4.7 created a huge amount of issues, none of which resulted in RB working.
Long story short, new laptop running Win 7 and Excel 2013 (About reports 32 bit version) and neither v4.7 or v5.0 (further, not even 32 or 64 bit versions) work. Nothing. Doesn't come up on the Add-Ins tab; going to add-ins under options shows that sometimes Report Builder bridge is active, sometimes inactive, sometimes not there (depending on the install or its mood).
This is hugely frustrating and I desperately need help. It would be enough just to get back to where I was before this mess but I can't. I am loosing a lot of time since many Excel dashboards are build around RB and they just cannot be run.
I don't know why there is still no official statement from Adobe.
Today, I got an answer from ClientCare. The issue we are facing is related to the language settings of Excel and the comupter. It is when the region settings change (on an English OS), to German, or French, or any other non-english language. This is really an excel issue, see: http://support.microsoft.com/kb/320369
We can fully reproduce this on our side (switch all language settings to english, then everything is OK in ReportBuilder).