schulze,

Only things I can think of are to up the pixel resolution of your Illustrator/Photoshop exports to at least, or perhaps as much four times, the pixel resolution of your video project and save in a lossless format like bmp rather than a highly compressed jpeg.

Regards,

Carl

Added:

Don't worry about dpi as it only relevant when printing. For example, you can have 1600 dpi but if the image is created only one quarter of an inch wide there will only be 400 pixels. Not nearly enough for your video!

The important parameter for video work is the absolute pixel size of the image. Check the quality you get using 360 x 240 pixels and say 1440 x 960. I'd go 2880 x 1920.

A transparency trick: If you name you file with an appended '_black' eg anything_black.jpg it will have black box transparency set automatically in MEP. Same is true for '_green', '_blue', and '_alpha'.