Hi A sk,
SapNetweaver 7.4 SR2 is based on SPS8 patches 0.
You don't nead to download Installation export as it is for ABAP.
You need to download the Java component CD 51048524_6 and 51048524_7.
Also do check the sapnote 789220 - Support Package levels for SAP NetWeaver installations/upgrades
With Regards
Ashutosh Chaturvedi