implode error for listing users

Hi

I’m using this code to create a list of users, but now I get this error message:

Warning: implode() [function.implode]: Invalid arguments passed in /home/virtual/madsrosendahl.dk/public_html/wp-content/themes/arras/personale.php on line 37

I’ve googled the problem and the common answer seems to be to disable cache, but I don’t have a cache-plugin installed 🙁

Can anybody help???

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