Profile works only once, then only <window id="main-window" appears

I have clean-installed Win 7 ulti Sp1 64bit on my desktop today. I used the same disk and installed the same up to date Ff. I copied the profile from the old installation, and installed it into the profile space of the new installation. It worked perfectly, but only the first time. After that no more Firefox, instead a small window appears telling me in red letters two lines:

<window id="main-window"

^

What happened? I did this kind of re-install before, and there never was a problem like like this?

Please help

Zitat von AngelOfDarkness

Warum in englisch? Sonst konntest du doch auch deutsch.

Versuche es mal mit dem abgesicherten Modus des Firefox.

Tut mir leid aber ich schreib den ganzen Tag lang in drei Sprachen