NPE in addRendition() - aem

Question

I am using to apply renditions to my DAM asset. Below is the code i am using
Node parent = resource.adaptTo(Node.class);
AssetManager manager = resource.getResourceResolver().adaptTo(AssetManager.class);
LOGGER.info("Parent path ===> "+parent.getPath());
if(!parent.hasNode(video.getVideoId()))
{
Node videoNode = JcrUtil.createPath(parent.getPath() + "/" + video.getVideoId(), "dam:Asset", parent.getSession());
Node videoContentNode = JcrUtil.createPath(videoNode.getPath() + "/jcr:content" , "dam:AssetContent", parent.getSession());
Node metadataNode = JcrUtil.createPath(videoContentNode.getPath() + "/metadata" , "nt:unstructured", parent.getSession());
//setting properties of metadata node
parent.getSession().save();
try
{
Resource childResource=resource.getChild(video.getVideoId());
LOGGER.info(childResource.getResourceType());
Asset asset=com.day.cq.dam.commons.util.DamUtil.resolveToAsset(childResource);
URL url=new URL(video.getThumbnail());
InputStream stream=url.openStream();
LOGGER.info("stream ::: "+stream.available()); //return 1059
asset.addRendition("vedio", stream , "jpeg");
LOGGER.info("asset.getName() :: "+asset);
}
catch(Exception e)
{
LOGGER.error("Error ::: "+e);
}
Error.log
13.06.2014 12:59:35.837 *ERROR* [pool-6-thread-4] com.adobe.training.core.YouTubeChannelImporter RepositoryException java.lang.NullPointerException
at com.adobe.granite.asset.core.impl.AssetImpl.setRenditionResource(AssetImpl.java:301)
at com.adobe.granite.asset.core.impl.AssetImpl.setRendition(AssetImpl.java:118)
at com.day.cq.dam.core.impl.AssetImpl.addRendition(AssetImpl.java:502)
at com.day.cq.dam.core.impl.AssetImpl.addRendition(AssetImpl.java:496)
at com.adobe.training.core.YouTubeChannelImporter.WriteNode(YouTubeChannelImporter.java:126)
at com.adobe.training.core.YouTubeChannelImporter.importData(YouTubeChannelImporter.java:71)
at com.day.cq.polling.importer.impl.PollingImporterImpl.importData(PollingImporterImpl.java:337)
at com.day.cq.polling.importer.impl.PollingImporterImpl.access$000(PollingImporterImpl.java:59)
at com.day.cq.polling.importer.impl.PollingImporterImpl$1.run(PollingImporterImpl.java:258)
at org.apache.sling.commons.scheduler.impl.QuartzJobExecutor.execute(QuartzJobExecutor.java:56)
at org.quartz.core.JobRunShell.run(JobRunShell.java:213)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:744)
This giving me NPE, I am creating the DAM nodes using jcrUtils. So in case something is missing property, please advice.