PSP X7 twain scan does not close dialog

[NfTaylor76]

I'm using the Trial version, so I can't pass this to Corel.
I've used PSP XI for years and am a regular scan user... PSP XI is working fine!

So, using PSP X7 32-bit, with a Canon MP640, the Scan icon (or File > Import > Twain acquire...)
MP640 is an all--in-one scanner and printer, it's connected by USB.
When I noticed the problem with PSP X7 I updated the drivers from the Canon web-site, but it made not difference.
I'm using the Edit window, and trying to avoid projects, "Manage", etc, as I use Picasa for cataloguing my images.

* the TWAIN dialog (Canon MP Navigator) mounts as a Modal dialog, and I can adjust and make the scan
* PSP acquires the image, and shows it in a window

** PSP XI closes the scanner dialog, and allows you to act normally, including making a new scan.
** sometimes PSP X7 closes the Twain dialog, as above.
** sometimes the TWAIN dialog is left mounted. It looks as though X7 is missing a final handshake with the dialog, as
*** the dialog won't close, but does go non-modal, so other functions become active
*** X7 will no longer scan (the scan button is greyed)
*** X7 won't close ([X] and File > Close are active but do nothing)
*** the scan dialog is active in almost all of its functions, except the Scan button does not work (but is not disabled)
*** PSP is active in most functions - I can iconise the scan window, edit and save files - just no longer scan nor quit politely.
*** no error codes - the only symptom is the dialog etc.

There's no sub-process running, and killing PSP X7 in Task manager (the only exit...0 closes the Twain dialog too - it's open within PSP.
"Find process" e.g. in Process Explorer, find the PSP X7 process.
I'm guessing its a threading issue...

[pearson100]

I actually am having this problem with PSP X6 and a Canon All-in-One printer. I usually have to go to the Windows Task Manager to stop the program. I can usually get 1-4 scans off fine but then the scan dialog box (called "ScanGear") won't close.

Somehow, PSP can't talk to Canon?