web brower proxy server error

Question

Ftp access thur web brower to external ftp site not related to sme or i-bays.
location from win2000 client machine thur sme 5.1.2 to isp to third party ftp site.
Outside to the real world. "ftpsite with full access"

Error in web brower - url:- "ftp://username:password@ftp.domainname/"

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the folder "ftp://username:password@ftp.domainname/"
is read only because the proxy server is not set up to allow full access.

to move, paste, rename, or delete files, you must use a different proxy. for information on changing your proxy, contact your administrator.

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ftp in set to public/normal

What is the problem,
Do I need to chance proftpd.conf - and are there how to's

thanks

griffo