Vault API: UndoCheckout failing

[ismangil]

Using Vault API 3.5.1, I am receiving:

Exception: System.NullReferenceException
Message: Object reference not set to an instance of an object.
Source: VaultClientOperationsLib
at VaultClientOperationsLib.ClientInstance.UndoCheckOut(VaultClientFile[] files, LocalCopyType localCopy)
at VaultClientOperationsLib.ClientInstance.UndoCheckOut(VaultClientFile file, LocalCopyType localCopy)

I have checked that the clientinstance and parameters passed to UndoCheckout are OK.

Any ideas?

[jclausius]

I would take a look at stepping through the Command Line Client's undo checkout code. Compare the parameters there vs. the parameters you are using. See if you can spot where something in the command line client's code for ProcessCommandUndoCheckout() is different.