I dont know what I am doing wrong Vn it should be in kips or lbs. I am new to the software.

The expression for Vn has the typical dimensional form; in fact, under the square root we have a quantity expressed as mass divided by length squared. In such cases one must downplay the automatic use of units of measurement. for example as shown below.

Please also pay attention to specify whether you want a mass to act as a mass or as its equivalent force.
If it is mass indeed, you should use lb or kg, but in case you want it to be threated as its equivalent force, always use lbf or kgf (or better, N or kN, this would remove any doubt).
SMath will handle everything in the proper way once you specificy forces in kgf, and consequent unit will remain consistent.

Bye

Thanks for your input, I made it work.