I tried to, but this is what happened:
Click on the little cog that says "options"
click on "video format" ans set the frame size to 720 x 756
click on the cog again and select "input source" Make sure composite video and PAL are selected.
click on the cog again and select "Mpeg Settings" and from the drop down list at the top, select "DVD PAL 720 x 576"
I clicked the cog, and on "Capture" tab I adjusted the video frame size to Custom 720 x 576 (the default is DVD 352 x 288).
Composite video and PAL were okay.
Then, on the "Capture" tab, after clicking Advanced settings and selecting "DVD PAL 720 x 576" and clicking OK, on the Capture tab the settings have returned to default, "DVD 352 x 288". Then, trying to capture video, I get the same error message about frame sizes as previously.