Out of stack space
Too many active Function or Sub calls. Check that both event and general recursive procedures are not nested too deeply and that they terminate properly.
A cascading events will cause this error.
Local variables require more local variable space than is available. Try declaring some variables at the module level instead. You can also use the Static keyword with Sub or Function to declare the entire procedure, in which case all local variables will be static. Or you can use the Static statement to declare static variables within individual procedures
Fixed-length strings use more stack space than variable-length strings. Try redefining some of your fixed-length strings as variable-length strings.
Too many nested DoEvents statements.
Use the "Calls" menu to view which procedures are active (on the stack).