Its a runtime error generated by the SBasic programming in your application. It is usually caused having too many or too few parameters on the call of a function or subroutine compared to the number it was expecting in its declaration, an excessive or improper use of goto statements or ThrowFocus calls, or array boundaries being violated.

Try commenting out sections of your SBasic code until the problem goes away. That way you can narrow it down to find the culprit.