Not a macro, but you can use group policy. I think it works in 2003, I'll have to check.
In 2013, this forces outlook to always disable one addin (0 value, I think its McAfee addin) and always enable others.
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Policies\Microsoft\office\15.0\outlook\resiliency\addinlist]
"UmOutlookAddin.FormRegionAddin"="1"
"OscAddin.Connect"="1"
"Mskoladd.MskOLAddIn"="0"
"Microsoft.BusinessSolutions.eCRM.OutlookAddIn.Connect.5"="1"
I'm not sure if outlook 2003's Resiliency key, which is under the office keys, works for addins - you can try it. The key is -
HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Resiliency
get the name to use from here
HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\Addins
or here
HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Addins