Jenkins TestLink Plug-in has extra logging, using java.util.logging. This can be useful when tracking issues, specially with result seekers.
There is a Wiki page that explains the Logging in Jenkins. You have to add a new logger for hudson.plugins.testlink. After you have configured this, you will be able to see logs like below. 
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Screenshot from 2012-07-20 15:37:29.png (image/png)
logging_testlink.png (image/png)
logging_testlink.png (image/png)
logging_testlink.png (image/png)