Invalid use of NULL

You tried to convert a NULL value to another value type. NULL cannot be converted to another value type.

For example, the function call CInt (NULL) is an invalid use of NULL. This function call attempts to convert NULL to an integer explicitly.

Implicit conversion of NULL is also invalid, as in the following sequence of statements:

S = NULL
For I = 1 To 5 Step S
Next

In a For statement, the step value must be numeric. LotusScript® attempts to convert the value in S to a number when executing the Forstatement. This is an invalid use of NULL.

Use the IsNull function to determine if a value is NULL.