FAQ/AJA Plugin 5.2
From VFXPedia
The AJA plug-in is produced by AJA, and the reason it doesn't work with Fusion 5.2 is that AJA have incorrectly indicated that the plug-in is produced by eyeon in the internal code.
Version 5.2 of Fusion now checks plug-in versions more strictly with eyeon native plug-ins to ensure correct usage and versions of eyeonscript. As a result of the previous AJA plug-in incorrectly indicating that it was produced by eyeon, it fails the versioning checks.
AJA will need to correct the problem and release a patched plug-in.