crystal reports problem when splitting parameter data

I use the following information to get information about incidents.

now I wanted to give the user the oppertunitie to let him split the data with a seperator.

when I test the code in sql, the code works and gives the data of the seleceted items.

now I added a parameter field.

When I dont use a seperator I get the results I want.

Now when I add the seperator Crystal reports gives the following error: