Cannot open your default e-mail folders.

I'm having this problem for two days. One of the users in the remote site cannot use her Outlook 2007 and she's getting this error message in the PC that she's using. She's connected to the MS Exchange 2007 located in the main site through VPN. By the way, VPN connection is connected perfectly. I connected to her system by means of a remote software. Her Outlook is completely appearing disconnected. It seems that the Exchange Server cannot resolve the username of that use.So I decided to go to the remote office and setup 

her email on my laptop but is running smoothly. I configured it easily without experiencing any problem.

So I created a new profile for the Outlook and I get this error:

"Cannot open your default e-mail folders. The file C:\Documents and Settings\USERNAME.DOMAIN\

Local Settings\Application Data\Microsoft\Outlook\outlook.ost cannot be accessed. You must connect to your Microsoft Exchange Server computer at least once before you can use your offline folder file."

To fix this problem, here are the steps that I took:

1. Open Control Panel - Mail

2. Create a new profile

3. Specify the Microsoft Exchange server or the FQDN

4. Put the username or the name of the user 

5. Dont click on the check name tab, instead go to More Settings >Security  and put the tick mark on encryption and click Apply.

6. Now you can click on the "Check Name" and now it will resolve the name.

Hope this helps!

Good luck!