Help!

I have Asus TV tuner and all major decent soft works
exept VirtualDub. I cannot set custom format 720x480/RGB or YUY2
Error 118 pops out - unsupported format. I have WDM driver so I dont
understand why VDub doesnt work in 720x480. Actually it gives the same
error in higher then 320x... capture resolution.
Please help. I'd like to use some filters and VDub would do this at one time
instead of reconverting huge files for hours.
Big thanks.