API - Disconnects During Import

While importing a list of users, I get an authentication error after 144. It seems the connection was dropped. How do I get arround this. Lists can be of any size.

I have been adding users 2 by 2 during tests, so this is not a bad login issue

Exception in component tMarketoOutput_1
AxisFault
 faultCode: {http://schemas.xmlsoap.org/soap/envelope/}Client
 faultSubcode:
 faultString: 20014 - Authentication failed
 faultActor:
 faultNode:
 faultDetail:
    {http://www.marketo.com/mktows/}serviceException:<name>mktServiceException</name><message>Authentication failed (20014)</message><code>20014</code>

20014 - Authentication failed