This wiki is regarding the message "Error when opening document with html control; DP_ERROR_GENERAL"
This message is seen at the bottom of the screen when the Document Viewer is launched to view a document.
This error is caused by a issue between the storing in the cache of a URL for a displayed document and the ECL viewer.
To resolve this issue goto transaction OAG1 and check the "Deactivate Data Provider Cache" option. Then save the changes and try to open the document again.
If the issue remains please implement note 1502912
SAP note 1502912: Document will not be displayed in ECL viewer