First, I obtained .LRN in a tarball from https://openacs.org/projects/dotlrn/download/ " .LRN 2.1.3 2.1.3 (8348k) The .LRN Education Solution"
The version of the package file-storage is <version name="5.1.0a15" url="https://openacs.org/repository/download/apm/file-storage-5.1.0a15.apm">
The URL that shows the error are http://10.10.10.36:7779/dotlrn/file-storage/file-add
Thanks a lot!