NSBeginAlertSheet not waiting for button to be pushed

Hi

I am having an issue with NSBeginAlertSheet() on 10.6.  (Don't know how or if it works or not on 10.5 with this iteration -- this app is in production with slightly different code on 10.5 without issue)

The code below lives in an object that sends a remote host a transaction and if the transaction returns an error it runs this Alert Sheet and previously (in the production code) the window passed in was [self mainWindow] which was a reference to the main app window.  I am now calling this object to do a transaction during a registration sequence and the window up is an auxiliary panel that captures registration info.  So I changed the window to be generically [NSApp keyWindow] as my thinking is that this should always use the correct window.

Now, when it is called it does in fact put the alert sheet up on the panel.  But the function ends immediately and does not wait for the user to hit OK.  This is true with "nil" passed in for the did-end selector or a selector being passed in.  If I pass a selector in, that selector is not called.

Any ideas?  

Thanks
Chad


             NSBeginAlertSheet(
                [reply objectForKey:@"errorMessage"],
                                        // sheet message
                @"OK",              // default button label
                nil,                    // no third button
                nil,              //no  other button label
                [NSApp keyWindow],                 // window sheet is attached to
                self,                   // we will be our own delegate
                @selector(sheetDidEnd:returnCode:contextInfo:),
                                        // did-end selector
                NULL,                   // no need for did-dismiss selector
                nil,                 // context info
                [NSString stringWithFormat:@"message with code %@", [reply objectForKey:@"errorCode"]]);
                                        // additional text