RFC_ERROR_SYSTEM_FAILURE - Illegal access to the right table of a LEFT OUTER JOIN.
RfcReceiveEx failed(RFC_SYS_EXCEPTION) RFC_ERROR_SYSTEM_FAILURE - Illegal access to the right table of a LEFT OUTER JOIN.
The function module Z_THEO_READ_TABLE in version 2.x only supports both Inner Join and Left Outer Join.
The SAP_ABA version which is needed to install Z_THEO_READ_TABLE 2.x must be > 740 SP04.
Please check your source status settings under More > System > Status > SAP System Data Details, see the following sample screenshot:
Left Outer Joins can't be used which Z_THEO_READ_TABLE version 1.x on older SAP Releases and needs to be done on destination side.