I'm using the approach as described here to create a folder in SharePoint. For some reason I do get the following error message every now and then.
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.
Apparently this does not have to do anything with an existing file or directory, or permissions to access the file. What in my case does cause this error, is the fact that the sharepoint listname has a length of larger than 50 characters.
Since this was not mentioned on the web according to my biggest friends Google and Bing, I thought it might help somebody else as well.