When you transfer projects from MS Project to Web TimeSheet to update the existing projects with new tasks, the transfer fails. The following error message is seen in the log file:

There were problems during transfer of project. Index was outside the bounds of the array.

When you transfer projects from MS Project to Web TimeSheet, the Integration Manager for Microsoft Project will first update Users to the Project.
This issue is noticed when the Users created in the Resource Pool of MS Project do not have the same Name Format as that of Login in name formula of Web TimeSheet (defined in the system preferences of Web TimeSheet).

Ensure that the user names in the resource pool of MS-Project match with the login name formula defined in the System Preferences section of Web TimeSheet.
For example if the login name formula is $FNameLower$LNameLower in Web TimeSheet then users created in MS-Project should be like anna dell.