Mail.app errors in Tiger

[jmc]

I'm having all kinds of grief with Mail.app. I can't send mail, even though the SMTP servers are connected and set up properly. I can't reply to mail either and nothing happens when I hit the reply button, choose it from the menu or use the right-click menu, nothing happens.

Looking in console, I see these kinds of messages after I've clicked a button and got no response:

2005-04-30 18:18:01.725 Mail[427] *** Assertion failure in -[NSMenu itemAtIndex:], Menus.subproj/NSMenu.m:713
2005-04-30 18:18:01.729 Mail[427] Invalid parameter not satisfying: (index >= 0) && (index < (_itemArray ? CFArrayGetCount((CFArrayRef)_itemArray) : 0))
2005-04-30 18:18:09.080 Mail[427] *** Assertion failure in -[NSMenu itemAtIndex:], Menus.subproj/NSMenu.m:713
2005-04-30 18:18:09.084 Mail[427] Invalid parameter not satisfying: (index >= 0) && (index < (_itemArray ? CFArrayGetCount((CFArrayRef)_itemArray) : 0))
2005-04-30 18:18:50.142 Mail[427] *** Assertion failure in -[NSMenu itemAtIndex:], Menus.subproj/NSMenu.m:713
2005-04-30 18:18:50.146 Mail[427] Invalid parameter not satisfying: (index >= 0) && (index < (_itemArray ? CFArrayGetCount((CFArrayRef)_itemArray) : 0))

Does anyone know what the problem is, or how I might fix it?