Solution to Drupal configuration: no access to pictures

For everyone desperately trying to fix the following problem:

I needed someone to give me a clue about my Drupal 6.2 or 6.3 configuration regarding pictures. I guess for someone who knows the programme longer than me (10 days) this had been an easy job:
I had problems of pictures not showing. Profile pictures of the users do not show. I was not sure about if the reason was .htaccess. It probably had something to do with the special requirements of my web hoster I thought.

I have read through other forum entries and looked at Google for several days, but I did not find a solution.

I tried to point to the user picture in the browser like this:
http://www.example.com/sites/default/files/pictures/picture-1.jpg

There was no access to the user picture.

But I received the following message:

Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, xxx@xxxxxxx.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
Apache/1.3.33 Server at www.example.com Port 80

AND

500 Internal Server Error

I tried around with CHMOD 777 on several directories to get access to the pictures, but this does not help either:

Forbidden
You don't have permission to access /sites/default/files/pictures/picture-1.jpg on this server.
Apache/1.3.33 Server at www.frankfurterresearch.de Port 80

There was another file .htaccess at /sites/default/files/ that I deleted. Now it works

(Urgghhh!! )

I use more often the search engine on this Forum now.