New, Strange Alert Box

[Michael Ron]

Has this happened to you? Do you know a fix? Suddenly I'm getting 
"alert boxes" with the yellow exclamation mark telling me "The document 
you are opening will open the application "Microsoft Word" (or 
whatever) for the first time. Are you sure you want to open the 
application?" Then tells me where the application is located with 
"Cancel" or "Open". I'm on  a G4, mirror door, 1.25  with OS 10.3.4. 
It's just started this. I don't know of anything I've done differently 
but probably did.
Thanks.
Ron
Memphis