License Craziness

First, I'm using version 5.1.3 (563.66) on a new PowerBook G4 running  
OSX 10.4.6 I recently moved my OmniWeb license from my old  
Quicksilver G4 to the PowerBook, placing the license in /Library/ 
Application Support/Omni Group/ Software Licenses (the system  
library, not my account's library).

Now, for no reason, sometimes OmniWeb will come up licensed, and  
sometimes not. I have no clue what causes this; it seems to be wholly  
random. Sometimes re-installing the license helps, sometimes not.

Any ideas? I'm not a software geek, so please keep an explanations to  
words of three syllables or less :-)

--Liz