funny ftp behavior

hi! help!

Hope this is the right place to post - Just joined the forum today.

I have a user that experiencing all kinds of bizarre ftp problems. He uses a cable modem provided by Cox. He is able to connect to my unix ftp server using both cuteftp and ws_ftp. He is able to cd and ls all directories in his account except two. These folders have called 'html' and 'DOCS'. When he attempts to cd into them, both programs time out. On this end I have check everything I can think to check from permissions to his quota. I am not able to duplicate the problem - I can cd into these folders with no trouble. Form outside of my network, using dsl from another provider I am also successful.

I have determined that the trouble is at least somehow related to the folder names. If I rename either folder he has no trouble (trouble is the directory's are both related a custom perl program and can not be left renamed). If I recreate the folder with the correct names, he times out. ??

I have spoken with Cox and they swear up and down that its nothing on their end, no proxies or firewalls (which I know virtually nothing about...) and say its more likely on his end. One tech at Cox suggested that he (my user) would need to reinstall his network drivers and tcp/ip set up. I don't do any Windows support and can't help him there. I just really want to know that I have covered all my bases here and if any of you think its on the user end, where, what, why? I am flummoxed.

thank you SO much.

-melissa