Dear All,
I have been bothered by this same Photoshop error 22 when trying to use the Photomerge feature or any other of the Automate features in CS5.
My computer is a Windows 7 32bit machine but this should definitely apply to Windows 64bit machines and possibly the same logic may apply to Mac but I do not know.
I didnt find a permanent solution but I did find a temporary fix which will at least allow you to use the function for one opening of the program however if you close and reopen photoshop the problem returns.
Temporary Fix Instructions:
1. Locate the file "Adobe Photoshop CS5 Prefs.psp" on your computer and delete it or move it elsewhere. (I assume by doing this you may lose ass of your photoshop preferences but it will allow you to use photomerge and HDR so you choose)
2. On Windows this file can be found in the User folder under C:\**USER NAME**\AppData\Roaming\Adobe\Adobe Photoshop CS5\Adobe Photoshop CS5 Settings\ (Replace **USER NAME** with the Windows 7 account user name)
3. After deleting this file or temporarily moving it out of that folder you can then open Photoshop CS5 and use the Photomerge feature as much as you'd like.
4. As soon as you close Photoshop CS5 the program automatically makes a new Adobe Photoshop CS5 Prefs.psp file so when you try to reopen the program it will not work again.
I hope this may be helpful to some people and I hope that Adobe can fix this issue, I have not and dont plan on submitting this as a bug report to Adobe, being that I do not personally own the program (still in 30 day trial) but anyone who would like to, please feel free to do so.