OK, that explains a couple of things. Since I was treating the method like a function, the function wasnt going have a reference for "self" It was also doomed for failure because I couldnt attach the alert to the carbon window. I've been trying to stretch my obj-c wings. Ouch that hurt. I'll try to work something else out. Thanks Bernie, W. -------------- > What am I doing wrong? Bernie wrote: It looks like you're trying to treat a method like a function. I think you need a c-wrapper. I've had limited success attaching Cocoa alert sheets to Carbon windows, mainly because (AFAIK) a WindowRef cannot be cast to NSWindow object. There are ways around it, but the sheet can occasionally become detached from the window. alertDidEnd: is a selector method, so I don't think it's going to work unless you create a class and stuff it between @implementation…@end.