What does this error mean?
2008-12-02T11:33:58+00:00,,"",,Update,,,,," Message: MyAccountUpdate: execution of AfterUpdate<LF><LF>caused by: System.Exception: Too many SOQL queries: 21<LF><LF>Trigger.MyAccountUpdate: line 8, column 25 Status code: 12"
The following error is generated when there is a custom APEX trigger (in this example "MyAccountUpdate"), that has not been properly optimized for batch processing. The trigger code will need to be updated to handle batch processing to avoid this error. There is some information on http://developer.force.com on how to optimize triggers. Search for "Too many SOQL queries" for more information.
Lowering the "Insert/Update/Delete Batch Size" setting in DemandTools (in the Preferences -> Options menu) or if using PeopleImport this can be done in Options (Update/Insert batch size) may allow the processing to complete successfully. The default is 100, but this can be set as low as 1. Please keep in mind though, that the smaller the batch size the more API calls will be used per insert/update, and there is a limit imposed by Salesforce on how many API calls are allowed in a 24hr period.