2434475 - SUM: function 'SPDA_GET_ADDON_QUEUE' failed with code 3 key LOAD_CLASS_NOT_FOUND: Class CL_OCS_EPS_FILE_READER not found.

While performing an Enhancement Package (EHP) upgrade using the Software Update Manager (SUM), the following error message occurs in phase PREP_EXTENSION/EHP_INCLUSION:

This trouble ticket was created by SAPup on YYYMMDDHHMMSS 
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SAPup broke during phase EHP_INCLUSION in module PREP_EXTENSION / Extension module
Error Message: RFC error system <SID> nr <Instnance ID> function 'SPDA_GET_ADDON_QUEUE'
failed with code 3 key LOAD_CLASS_NOT_FOUND: Class CL_OCS_EPS_FILE_READER not found.
If you put new packages in the download directory, use option 'init' to upload them

• Software Update Manager (SUM)
• EHP<version> FOR SAP ERP 6.0 environment

Enhancement Package, EHP, Software Update manager, SUM, PREP_EXTENSION/EHP_INCLUSION, SAP ERP 6.0, Error Message, RFC, function, SPDA_GET_ADDON_QUEUE, failed, code 3 key, LOAD_CLASS_NOT_FOUND, class, CL_OCS_EPS_FILE_READER, not found, 212902, memory pool, size, abap/buffersize , KBA , BC-UPG-TLS-TLA , Upgrade tools for ABAP , Problem