Try changing InForm\InForm.ui to InForm/InForm.ui
The IDE is actually pointing to an error in line 14 inside InForm.ui, which means it was found despite the mix of \ and /.
Line 14 of InForm.ui is actually referencing the falcon library. If it's sitting next to the qb64 binary it should definitely be found;
What distribution is this, johnno56?
Another thing to test: can you copy the DECLARE LIBRARY block that begins on line 14 in InForm.ui and paste it into a new blank program? Does that give an error as well?