this problem is familiar to me, same happens also to some other settings.
And on some computers (not at users PDM).
1. If it is a problem of the registry settings - it is possible to change them several times and to see where there are these settings. I think it it is possible to try to find out on the computer where there is no such problem. Then to compare to the problem computer.
There are many programs which monitor changes in Registry (for example RegOrganizer).
2. If it is the user's problems - try to log in under other user and check existence of a problem. To try to replace the owner, to increase the rights, etc.
3. If it is system problems - add all PDM folders to antivirus exceptions, disconnect service of protection of the software, try registration of some *.dll, establish start of all programs with the rights of the administrator, etc.
4. If it is installation problems - try to correct it or to reinstall EDrawing (sometimes the previous installations create problems). It is possible to reinstall all packages from the Preregs folder (on install disk).
I think that it is a local problem - therefore probably the reasons can be much, and there is no universal decision probably (it would be very desirable to be mistaken).
If I have time - I will also try to find out something (there are same problems, and on several computers). And it does not depend on the version of PDM.