Expected expression before end of argument list for: <function name>

You used a comma before the last optional argument in a call to a built-in function, but you did not supply the argument. For example:

myVal% = StrCompare("abc", "abc",)          ' Illegal 

Remove the comma, or specify the last optional argument:

myVal% = StrCompare("abc", "abc")           ' Legal
myVal% = StrCompare("abc", "abc", 1)        ' Legal