Directory create failure
The directory creation failure error usually refers to the Workdir.
Your application will require suitable read/write permissions for the Workdir and/or its parent directory if it doesn't exist. The Workdir is usually specified as a parameter to NalpLibOpen(); if omitted, the default is CSIDLCOMMONAPPDATA/Nalpeiron. See https://docs.microsoft.com/en-us/windows/desktop/shell/csidl for further details.
Solution
Check directory access permissions and parent directory access permissions for the user in question; read/write is required.