This AppleScript error message can occur when smart quotes are used instead of straight quotes in a script statement. The Perform AppleScript script step will compile statements with straight quotes only.
This may be an issue when you copy a script from a word processor that uses smart quotes and paste it into the script text area of the Specify AppleScript window. This may also be an issue when using the field value option in the Specify AppleScript dialog box (your AppleScript is in a FileMaker Pro field). If this is the case, turn smart quotes off (in File Options) to avoid the error.