I have an Excel file exported from a third party tool, with a field called "Policy Number". I created a custom account field in salesforce.com. The file contains text entries of activities entered by salespeople over the years. I want to import those activities into salesforce.com so that they are shown related to the accounts. 

I downloaded the Excel Connector, but I get errors every time I try and log into salesforce.com I get the error: "Error generated by request"INVALID LOGIN:Invalid username, password, security token, or user locked out. Exception code 5078."

Any ideas what is causing this? I have tried getting a new security token several times, and the login information is absolutely correct. Help would be most appreciated. I'll pay someone that helps me fix this.