I downloaded the Director Suite 2 trial including PD12.
I already have the original Director suite (including PD11) installed.
PD 11 had no issues.
I can't say for sure but I believe that Photo Director 5 messed up my Photo Director 4 in that I am unable to open certain jpegs in certain folders which I didn't have issue with before.
I can take the offending jpeg out of a folder (say A), move it to a different folder (say B), then both Photo Director 4 (and 5) open it without issues. Many other jpegs in folder A open without issue and were taken with the same camera at the same time with exact settings. Just certain ones don't open directly from "import". Photo Director 4 didn't have this issue till the trail install. Upon removal of the trial, the problem persists though. This is why I can't nail it down exactly.
Probably more info than you wanted