Well, it would depend 50% on how fast you spin the encoder, and 50% on the resolution (250ppr)
In short, No, you can't use that card. The input refresh is (I'm recalling from memory, not a manual, so look it up if you need exact numbers) 8ms, plus your scan time - let's estimate 12 ms.
So the BEST you would get out of that car is 1cycle/20ms = 50 Hz. But, you also want to have at least a 2:1 ratio when using ladder scans to count, so you'd get - at best - about 25Hz.
You would need a HSCE or HSCE2 card to input that encoder. They go up to (again, from memory) 50kHz.