Errors using Node for File Uploading

Hi all,

I have a Node (FileNode) and 2 attributes under FileNode, fileName (string) and fileData (binary).

FileNode

- fileName (string)

- fileData (binary)

They are assign to the FileUpload UI element, data and filename respectively.

In my wdDoInit(), it throws a null pointer exception when it reaches this statement. attributeInfo.getModifiableSimpleType();

IWDAttributeInfo attributeInfo =  wdContext.getNodeInfo().getAttribute(IPrivateKnowledgeManagementView.IFileNodeElement.FILE_DATA);
attributeInfo.getModifiableSimpleType();

What could be the reason?