Recently got this card. Was very impressed.. but I've mostly been using the FW side of things. Other day I needed to make some color prints (have an Epson 870 - USB).. ooops. It gets from 5 to 85% of the way through printing the image, then craps out with a "communications error." Every time.
Tried my whole bag of tricks.. mostly deleting and re-installing various software pieces that are part of the printing chain. Got very frustrated and took a pristine clean partition and did the whole 9.1 thing there (before I even COPIED anything to that partition I tried to set up all the stuff.. except that the "Startup Disk" application kept crashing.. all the time.. wonderful OS software, eh?). Installed the printer drivers, the 2 libs for the card and tried to print.. gak, EXACT same error.
Given that I USED to have a super el-cheapo USB card and printed just fine, it seems that there's a problem with the card. Data is clearly being passed through the USB channel, but it's getting killed at some point.
I wrote to them, but I haven't heard back in 2-3 days so I thought I'd turn here to see if anyone has any clue.