Workflow rule condition question

Hi fellow CRMOD champs.

Again I'm struggling with the Expression Builder.

The syntax of the workflow rule condition gives me the following error:

"The definition of integration component field 'pllEmail_to_be_sent' for integration component Çontact' in integration object 'Contact_Occam' is invalid.".

I am probably not using the special characters around the fields in a correct manner.

Here is the expression that I'm using.

[{plEmail_to_be_sent}]=LookupValue("OCC_CUST_LOV_CONTACT_46", "1.BKR afwijzing B2C")

AND IfNull([{plEmail_to_be_sent}], "Invalid") <> IfNull(PRE('<plEmail_to_be_sent>'), "Invalid")

AND PRE ('<plEmail_to_be_sent>') <> [{plEmail_to_be_sent}]