I am trying to delete a file from SharePoint using the list web service which is failing with the following error.

• Error Code: 0x81020030
• Message: Invalid file name
• Detail: The file name you specified could not be used. It may be the name of an existing file or directory, or you may not have permission to access the file.

The update XML I sent through is:

<Batch OnError="Continue" PreCalc="TRUE" ListVersion="0" ViewName="{8FE4E2C8-939E-4462-ABA2-D633EED7F76E}"><Method ID="1" Cmd="Delete"><Field Name="ID">84</Field><Field Name="FileRef">http://win-4h0xp59sn75:40414/Shared%20Documents/del.txt</Field></Method></Batch>

The SharePoint server error logs indicate:

• ERROR: Failed to OpenThreadToken, LastError=1008
• The file you are attempting to save or retrieve has been blocked from this Web site by the server administrators.

Things I have tried

• I've tried the changes in #1372971 which has no helped.
• I have also tried the changes recommended on the Microsoft Social site, which has also not helped.
• I have confirmed that the txt file extension is not blocked as indicated here. In addition I can remove the file via the website, it is just on the web service that this fails.

The permissions are correct (or rather not in play) as I am running as a SharePoint administrator, which is the same account that uploaded it via the copy web service.