If the light's on, then you have issues with it.

Assuming it was working before the MS replacement...

When you put on the new MS and bled it, did you remember to bleed the ABS unit as well and top its fluid off, etc.?

I have a '95 Accord whose ABS unit went out after about a year and a half of ownership (I bought the car new.). After the dealer quoted me around $1500 to fix it, I've been driving without ABS ever since...