Inconsistent Revlet launch

[Rick Rice]

Has anyone got any suggestions as to what I can do to deal with the  
following.
I create a standalone revlet which may or may not run. The revlet  
might run as expected several times then fail to run and then if I  
launch it again it might run. If I launch a browser (Safari or  
Chrome) and then open the html file created along with the revlet I  
get either a black box the size of the app or the progress bar hung  
around the 5% point. It doesn't make any difference if I empty the  
browser cache or reset the browser. This happens on my Mac OS-X 10.4  
and 10.5 on Safari 4 and 5 as well as Chrome 8. I'm using LiveCode 4.5.1
Thanks
Rick