OK. I've tried with ftp://user:firstname.lastname@example.org and with ftp://email@example.com and neither seem to be working with Internet Explorer. It looks like you are logged in but you cannot see any files that are there or transfer any files there.
Getting in the way I originally described (with the error message) does work, but it is not acceptable to my main client (he needs to be able to tell his clients how to access the ftp site and thinks telling them to click off an error message is unprofessional). He is quite upset with me over this and I am getting very frustrated. Is there no other way to do this through Internet Explorer? Maybe something on my end was configured wrong when setting up my ftp site?
On another note, I did manage to get a php upload script installed on my home page, only to find out that there is a constraint that files can be no larger than 2MB. I hadn't realized this because the script itself allowed me to set file size as large as I wanted and it was only after I told my client he could upload files this way and it didn't work that I looked into it and found about about this constraint that is apparently on the server end. Needless to say he was not happy with me after this either! The files that I need to receive are as large as 75MB.