Rohan
As suggested by Rakesh, please go through the links from Indrajit to setup your QA ECC connection to SLD first.
Here is also an additional link from SAP library for your reference.
http://help.sap.com/saphelp_nwpi71/helpdata/en/0b/8512417301ee6fe10000000a1550b0/frameset.htm
If you are still getting error, please provide screenshot of your error when running SLDCHECK in your QA ECC system. There are a few steps being executed during the check and it would be easier for us to assist you if we know which step you are stuck at.
Rgds
Eng Swee