SYMPTOM:
As of Strategy 9.4.1 Hotfix 1, .mstr files that were created in Strategy Analytics Desktop can be imported into the Enterprise Platform using Strategy Web. This .mstr file contains both the dashboard and the dataset required by the dashboard.
After importing this dashboard, execution may fail with the following error:

(SQLEngine got an Excepttion from DFC: The user running this Report Services document does not have the privilege to access a base report that uses multiple data sources!Internal Error: DSSDocumentExecuteTask::Run(): Error calling DocumentInstance::Execute() , job 277, Error Code=-2147212800.)