I have a simple form in VB.Net with some combobox filled with text from an array.

The error message i'm getting is:

An unhandled exception of type 'System.ArithmeticException' occurred in system.windows.forms.dll

Additional information: Overflow or underflow in the arithmetic operation.
Everytime the form looses focus after filling the comboboxes with this array it crashes with the above message.

I am filling the comboboxes with the following code:
Code:
Dim cname() As String

        '    Get number of system components - TQNOSC(number of system components variable, noerr)
        Call tqnosc(nscom, noerr)
        ReDim cname(nscom)

        For i = 1 To nscom 
            '        Get names of system components - TQGNSC(Phase index number, component name, noerr)
            Call tqgnsc(i, cName(i), noerr)
            Species1_Combo.Items.Add(cName(i))
            Species2_Combo.Items.Add(cName(i))
            Species3_Combo.Items.Add(cName(i))
            Species4_Combo.Items.Add(cName(i))
        Next i
To duplicate the error I run that code and select something in one of more of the comboboxes then leave the form (minimise or just switch to a different program)

Any ideas ?? Can't seem to use the combo box without the form crashing all the time !