Custom Expression IIF Statement Assistance

Hi 

Wondering if someone can help me get the expression correct. I need to achieve the following in a Custom expression. Ive described what should happen below...

IIF(Eq(employeeCategory,"Disabled")   FLOW "514"
IIF(Eq(employeeCategory,"CategoryB")   FLOW  "512"
IFF(Eq(employeeCategory,"CategoryC")   FLOW "512"
IIF(Eq(employeeCategory,"CategoryA")   AND   IIF(Eq(employeeStatus,"Disabled")   FLOW= "512" 

This is what ive come up with:

IIF(Eq(employeeCategory,"CategoryA"),IIF(Eq(employeeStatus,"Disabled"),"512",IIF(Eq(employeeCategory,"Disabled"),"514",IIF(Eq(employeeCategory,"CategoryB"),"512",IFF(Eq(employeeCategory,"CategoryC"),"512",+userAccountControl+))))

Just getting "the function IIF is not correctly formatted".

Appreciate the assistance

-stu