Gnucash 1.6.6 on RedHat 7.3 only starts as root

[Daniel Brahneborg]

Hi,

I started using gnucash a few weeks ago, and it has worked pretty fine.
One day I made the mistake of starting it as root, and since then it
absolutely refuses to run when I'm my usual user.  It complains about
not being able to get the lock for the data file, and then it just
stops.  When running it with --loglevel 6 the output ended with the two
lines
Enter: gnucash_ui_init
Leave: gnucash_ui_init

What do I have to do to get it running again?

Lots of thanks,

/Basic