Cubase 6.0.2 channel monitor and MOTU2408 Output Problem???

I have a serious problem with the outputs when channel monitor is turned on in cubase.

I output my line signal from the output and hear random crackling noise at the other end. Troubleshooted every step and it’s still crackling.

When I use MOTU CueMix console to route the signal, everything works fine…Outputs sound clean…

I have tried different buffer settings in Cubase and it’s still crackling… is this a software issue??? I didn’t have this problem on a mac. I am new to PC…

The idea was to Output the guitar from Cubase DI and send it Line out to reamp box.

Configuration:

Windows 7 Home Premium
Cubase 6.0.2 (64-bit)
Gigabyte Z68 UD3 Motherboard
16 GB Ram
Intel 2600k CPU

MOTU2408 MKII