SharePoint 3.0 destination folder error when uploading pictures

Hello,

I have a client who had me setup SharePoint 3.0 on one of their servers recently, but the user that will be doing the uploading of pictures and documents is receiving an error when she tries to upload:

"Microsoft Office 2010: The destination folder http://intranet.domain.com/Employee Appreciation Day 2012/ is not available. The folder may have been moved or deleted, or network problems may be preventing a connection to the server."

I think the main problem here is that she and the other employees will be using an internal DNS record called "intranet.domain.com" that was created for their use to reach the SharePoint server, instead of using the internal DNS record of the server itself (http://servername). The SharePoint Central Administration is reached using the http://servername address. The users can reach http://intranet.domain.com just fine, but they still receive the message above. I believe it is because SharePoint is only recognizing http://servername/Employee Appreciate Day 2012/ as a valid directory, but not http://intranet.domain.com/etc.

In the SharePoint Central Administration, I have gone into the Operations tab, and changed the settings within Alternate Access Mappings by adding http://intranet.domain.com as an Intranet mapping, but the user is still encountering the issue. I had them try connecting to SharePoint using http://servername and they are able to upload just fine.

Is there anything else I'm missing? I'm very new to SharePoint, so I have no idea where to look next.

Thanks!