the Load-Command searches for the lob-files on the Server. There's a hint in the Documentation that for load-client the lobs-file have to be stored on the DB-Server (and the instance-owner needs access to the Files).
It's not specified for the Import-Command, but i guess it's the reason for your issue. Try to copy the LOBs to the Server and specify the local path (on the server) in the import-file.
1 Either the path "<path-name>" is not a valid sqlu_media_list or
the values provided are not valid. The media_type must be
SQLU_LOCAL_MEDIA and all path names must be terminated with a
valid path separator.
2 There is not enough space on the paths provided for the EXPORT
utility to hold all the data of type "<type>".