[Dovecot] Cant log in to my new install :(

Hi, I have just built a copy of dovecot on my sparc based solaris box. I now have dovecot running but when I try to log in using thunderbird or the solaris default package I get bombed out and the following error is generated....

dovecot: Nov 09 21:42:57 Error: child 20780 (imap) returned error 89 dovecot: Nov 09 21:42:57 Error: imap(ppchurch): flock() locks not supported

I have set the lock method to fcntl and restarted dovecot but I still get the same error ...

anybody else seen this before?

Thanks

Peter