HSMExpress + UCCNC Post Process Problems

Hello!

I just bought a Stepcraft2/840 and almost have all the mechanical issues figured out (what a mess!).

Now, I'm having issues importing a test piece that I want to carve. I'm using Solidworks + HSMExpress and I'm using the Mach3 post processor file that comes with HSMExpress. When I generate a job on a 3"x5" work piece, and import it into UCCNC, the tool path seems to be ok except for a couple points where the machine seems to go to very long Y values. Please see the attached screenshot. Because of this, UCCNC thinks the work piece is much longer than it actually is.

Does anyone have a post processor file to use for the S2/840? Can't seem to find this anywhere, and I'm thinking my problems are because I'm using the generic Mach3 processor.

Any help would be greatly appreciated as I am stuck with this.

Thank you in advance for your help!