Also check read/write permissions to these folders:
C:\Program Files (x86)\Bentley\AECOsimBuildingDesigner V8i Ss5\AECOsimBuildingDesigner\ServerApp\bin\
...\WorkSpace\BuildingDatasets\Dataset_US\symLibs\
(this folder is wherever you have located the shared workspace, or on your local machine as mentioned in your testing)
Not every user needs write permissions to the symLibs folder, only users that are editing or creating symbols.