Blackberry FileConnection IOException: User Key Null

In my Blackberry application I am trying to write to the File System using the FileConnection class. I am able to open the file connection using:

(FileConnecti开发者_Python百科on) Connector.open(tempFile);

but when I call

tempFileConnection.create();

I get an IOException and the message is User key null. This is only happening on the Bold 9000, on other devices it works fine. The name of the file that I am trying to create is file:///store/home/user/rootTest.tmp

Does anyone know what User Key null actually means in this context? Is there any reason (IT policy etc.) why I wouldn't be able to write to this directory?

Apparently this is a mystery, not even anyone on the Blackberry developer forums can answer this one. Chalk this up as another RIMtarded experience.