It says the syntax error is on line 7 of card script 4. If you look at line 7 in the card script for card 4 you'll see this (there is a space between the 2nd event and 2):
event2 = event 2 + 1
The line should be this:
event2 = event2 + 1
That fixed it.
Also you should put an END TIMER as the last line in the card script to close the ON TIMER block. GameMaker does it internally for you if it reaches the end of a script with an open TIMER, MOUSEDOWN, or MOUSEUP block, but it's good practice to make sure you do it properly.