Not printing properly to Zebra 2844 after upgrading to Windows 7

I just replaced an old XP machine with a new Windows 7 machine. After connecting the printer and installing Shiprush, I am not having any luck getting FedEx labels to print properly. They are starting about halfway down and then spanning to the next label. As far as I can tell, I've properly specified the media size of 4" wide by 6.75" long (I'm using the doc-tab labels). I also installed Dazzle, which we use for postage printing and that software seems to be printing properly (although not very dark).

Anyone have any suggestions?

Thanks,
Paul