Sorry for the delay. The error implies that the connection is throwing an error or has a space in the code.
The error states: "output started at /home/folder/domains/domain.nl/public_html/cms60/start.php:1"
That means that the first line is outputting code to the page and a connection shouldn't be outputting code. Are there any blank lines, spaces, or other code on that line or in the referenced include file from that line? Is the connection information correct and not throwing an error? That is what would be causing this error.
If you give me FTP access I could debug and tell you precisely what the problem is.