ewood to cable forum
Not an easy one to solve I suspect.
Presumably you are running Outlook 2003 when OE is not running. Do you have Outlook 2003 set in tools> options > send / recieve (send immediately when connected ticked) to include your account. and that auto send recieve is active? Is Outlook working online or offline (cached)?
Are you on dialup or broadband (cable or ADSL)?