first copy & paste not working

[Joe Bloggs]

I have the following lines my .emacs file for supporting cut & paste between 
applications:

(mouse-sel-mode 1)
(setq x-select-enable-clipboard t)
(setq interprogram-paste-function 'x-cut-buffer-or-selection-value)

However, after starting emacs, the first cut/copy from within emacs is not 
recognized. In other words, the first time I do a yank, it pastes whatever I 
last copied outside emacs, even if I just did a cut/copy within emacs. I can 
only yank my emacs text if I repeat the emacs cut/copy, othewise it just keeps 
yanking the external text.
Can anyone help?