Outlook 2003 can't send-receive POP3 or Exchange

[Cascader]

We have a network with Exchange 2003 on Windows 2003 SBS. Everything
works fine for most of our client PCs (all Windows 2003 with Office
2003) except 2 machines:
1. The first one complains about dll not registered and script errors
when opening Outlooks Home Page. Nope, it doesn't say which dll... Tried
Repair, Reinstall, Uninstall & Install, same problem. It also doesn't
Send - Receive. Not a POP3 account, nor Exchange Account. When I "Test
Account Settings" for the POP3 it all works fine. The user can also see
his/her mailbox on Exchange but can't send or reply to anything. No
error messages on that attempt, the status bar says "Connected" and
doesn't change during Send/Receive. The user has access through Outlook
Web Access.
2. The second machine just can't send / receive like the first one.

Any ideas?
TIA...

 

[Cascader]

We have a network with Exchange 2003 on Windows 2003 SBS. Everything
works fine for most of our client PCs (all Windows 2003 with Office
2003) except 2 machines:
1. The first one complains about dll not registered and script errors
when opening Outlooks Home Page. Nope, it doesn't say which dll... Tried
Repair, Reinstall, Uninstall & Install, same problem. It also doesn't
Send - Receive. Not a POP3 account, nor Exchange Account. When I "Test
Account Settings" for the POP3 it all works fine. The user can also see
his/her mailbox on Exchange but can't send or reply to anything. No
error messages on that attempt, the status bar says "Connected" and
doesn't change during Send/Receive. The user has access through Outlook
Web Access.
2. The second machine just can't send / receive like the first one.

Any ideas?
TIA...

Oops... That was "Windows XP with office 2003"...