FireFox and NFSv4

[Andrea Venturoli]

Hello.

For years I've had my home on an NFSv3 server.
Finally I decided to move to NFSv4.

Now the following happens every now and then (let's say, 1 out of 5 
times I launch it):
_ FireFox is closed (no process running);
_ I open FireFox and, while it works, a red message appears saying:
"The bookmarks and history system will not be functional because one of 
Firefox's files is in use by another application. Some security software 
can cause this problem";
_ I can close FireFox, but I'll have to wait for a while to reopen it, 
or I'll get the "Firefox is already running but not responding" window.
_ After a while I can open it again with no warning.

Nothing to really worry about, but I'm curious (and would like to be 
sure no latent problem is there).

Of course I beleive the reference to "security software" does not apply 
to UNIX systems; I don't think anything is accessing FF files either.

What should I check?

  bye & Thanks in advance
	av.