I have raised a defect using autodefect logging. How can I link the raised defect to current issue?

[Sajitha]

I am using SIL script for raising Defects.

Defect=createIssue(Projectkey,"","Bug",Issuesummary ,"",issue_description,"","","","","");

Then I am trying to link the raised Defect to my current issue(Story) within the same SIL script.

linkIssue(Defect, key, "Blocks");

But linking the defect is throwing exception in logs and my customfield is dropped from reindexing. Can someone suggest how to link the raised defect to current issue?