I don't think that is going to be it because I was notified of this problem by a customer who had downloaded our program but couldn't start it. To verify the problem, thinking maybe he got a corrupted download, I downloaded the same file and installed it but got the missing Trial.dll error message when I tried to run it. The verify that some corruption didn't happen on the upload, I used the original file compiled by AI to do an install and got the same error. I verified that the Trial.dll was, indeed in the main application directory but the error was saying that it couldn't be found. I then copied the copy that I had in my main developer directory over to the main installed application directory and I could then run the installed copy.
I haven't updated or changed AI in any way since last month when AI produced a valid Trial.dll and I hadn't changed the source of the Trial.dll from the previous version to the current version.
When I get time I will play around with it some more but I was thinking that you had heard of such a thing happening in the past. It was just very odd. I will, for the hell of it, turn off any anti-virus and install the bad copy just to see what happens.