I too am having this issue with CS5.5 Web Premium. Can we get instructions for installing to a Suite? Come on Adobe, why does this always happen to the Suites? Don't you test this case?
Yes, I am having the same problem. CS5.5 Web Premium serial number doesn't work even though FB 4.6 is supposed to be a free upgrade?
The information is here - http://kb2.adobe.com/cps/924/cpsid_92402.html
and I found it from here - http://kb2.adobe.com/cps/921/cpsid_92181.html
Very strange, but Flash Builder 4.6 accepts the serial key after the installation (not before installation) if you are using a Creative Suite (in my case Web Premium) serial key.
Yes, that is the fix as I discovered yesterday by just going for it. My larger point is that Adobe should have pointed that out up front. That is NOT normal install behavior for software. Why would I assume that my serial number would work if it FAILS during the install? This is not the first time I've had diffuculty with the serial numbers on Suite installs.