Hoping someone might be able to help out with this because I've tried everything I can think of.

Just installed the upgrade to X2 Producer from X1 Producer and all of the Cakewalk Plugs and 3rd Party Synths work but the 3rd Party Audio FX don't! I've tried resetting the VST paths and rescanning the folder. It sees them in the scan but they don't show up in the Audio FX folder.

They all worked perfectly in X1 and I've installed the hotfix and followed the advice through on the Knowledgebase about Short Names http://www.cakewalk.com/Support/kb/reader.aspx/2007013293 but this hasn't fixed the problem - I still can't access my 3rd party FX!

Any help would be much appreciated if anyone else has had the same issue.

Are you using the Default-All Plug-Ins Layout on the Audio FX menu? (Right click the Fx bin, Audio Fx, Plug-In layouts. 

If that doesn't solve it, go to Utilities-Cakewalk Plug-In Manager and make sure those plugs are included in your layout. 

other ideas.. (other than location) are you are screening for 64bit plugs and they are 32bit.. or your fx plugs show up as instruments

run as admin?