MENU ASPECT RATIO ERROR UPON BIULD

All,

I wondered if anyone may be able to help... I've been constructing my company's
showreel DVD using ENCORE over the last few weeks, encountering a mixed variety
of unpredictable bugs along the way. Just when I thought I'd cracked the
project, I've started to encounter a very troubling error that prevents me from
build a finished DVD.

Upon Building, i continuously get the following message attached to a variety of
different menu file names:

PGC "menu file name" has an error at 0.000s. The aspect ratio of this
file is not supported by DVD. -PGC Info: name = GGN_MENU_FORD_story.ref= EBpgc,
time = 0.000s

I presumed that this was relating back to the pixel aspect ratio of the menus
upon creating in Photoshop, but the frustrating thing is that i haven't changed
these ratios from successful builds on earlier versions of the disk. I'm loathed
to start unpicking the project...

Any ideas? Thanks,