Dance Factory Dance Mat Problem

[Crimson Wolf]

It's this mat, but for PS2:

Buy USB Dancing Mat - Order Now!

I just bought this dance mat today, it's brand new and works fine with my PS2. However, with Stepmania I have two problems with it:

1. There seems to be a split second of lag between hitting the arrows and it recognizing them

2. If I have my foot on one arrow, I can't hit another one. However hitting two at the same time works fine.

I am using a PS2 -> USB converter, so whether that makes a difference? Any advice would be great.

I've tried the StepMania forums, but they're pretty inactive. And sorry if this was the wrong board, I didn't know where else to put it.