this is a longshot, but make sure you are linking to the proper photoshop .exe file ....
best way to check is to look at the shortcut you use to start up photoshop outside of iclone.
The reason this comes to mind, is that if by chance Adobe updated the file and you linked to an older version of photoshop, this is the error that would happen, since the older photoshop.exe would probably not work with updated files. For instance, iclone 6, and iclone 7, both use iclone.exe as a starting file, so it's easy to confuse the files if you don't check directories and look for latest version. The other thing is if by chance you are using a special string command in the start up shortcut - like some softwares do, ie - software.exe /r, this could also be answered by simply looking at how the shortcut file is invoking photoshop - if you need to add a special command, you "might" have to add it to the .ini file manually - not sure about this because I've never had to do it, but I have tinkered with ini files and know any special changes that can't be done in iclone ui , can be done there.
It's highly unlikely that iclone itself is causing this because iclone doesn't do anything special with the external programs other than start them and send an image to them - there is no advanced integration process, just a shortcut within iclone. so you have to troubleshoot outside of iclone and the way photoshop is being invoked.
I hope this helps, and good luck.
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"To define Tao is to defile it" - Lao Tzu