When running the SQL C2 report "Administrative users activity [windows]" via Quest Knowledge Portal (QKP) you receive an error similar to the following:
"An error has occurred during report processing.
Cannot read the next data row for the data set MainDataSet.
Invalid length parameter passed to the SUBSTRING function"
The event's string value which holds the data the report uses contains unexpected spaces which cause a parsing problem during report execution.
1) Download the attached report ("Administrative_users_activity_[Windows].rdl").
2) Upload to SQL Reporting Services via the SSRS Reports GUI.
3) Configure to use the appropriate Shared Datasource via QKP.
This issue will be resolved in future releases.