cmom

Thanks Panjab for your interest. Already solved.

Regards,
Claudio, aka cmom

Thanks esmi.

1. Exclude all inactived plugins;
2. Inactivate all active plugins. Problem disapeared.;
3. Re-activate plugins, one by one, testing the result. After all of them re-activated the problem has gone!

Took advantage to remove some that, though activated, were of no use.

Thaks for the help. Regards,
Claudio, aka cmom

Ok. Will deactivate all plugins to check right away;

Have already re-upload all files & folders, except the wp-content folder, from a fresh download of WordPress;
Already switched to Twenty Eleven;

Wiil keep you posted. Thanks,
Claudio