Buggy Firefox opening via "Run" box

I use to go to alt+f2 to open run box and type app name to open my stuff instead of traveling by the menus. I prefer a very clean desktop/bar, so i don't use to put any icons on it.

When i try to open Firefox this way, it often simply doesn't open.. Instead, it goes to the taskbar with that hourglass and the firefox ball goes jumping on my cursor, but doesn't open. It goes like this for some seconds, like 20, and then looks like it gets killed.
When it takes like more than few seconds to open, i understand that's goin to happen and simply open it again, which use to go normally.. But now, that always bothered me. That happens like once in each 4 times i try to open it.

I googled it but found no info. Anyone got a clue? Thanks in advance!

Btw, i use Kubuntu 7.10. My old computer has the same issue with the very same Kubuntu on it. I used to wait for a new Firefox release to check if it would get fixed, but nothing until today. Oh, that's only with Firefox, btw.

 

Did you check your iso with the mdsums?

 

As Thomas stated, it could be a corruption in the Kubuntu iso you used to install from.

OR a corruption in the firefox installation. So open up synaptics, searh for firefox, right click on firefox results with a filled green box next to them and select mark for re-installation.