SFTP error Assertion failed

I get this error when I try to FTP from an HP Alpha Server to a UNIX box.

FATAL: BUILD13$:[TCPIP_V54_BLECO7.SRC.SSH2]SSHFC_TRANSFER.C;1:1835 SshFCTransfer (function name unavailable) Assertion failed: tdata
->current_dest_file->attributes->flags & 0x00000004

the sftp /put fails just before it does the actual transfer.

When I log back in the filename is in the UNIX directory but with 0 size.

I would appreciate any suggestions.

Thanks

Check if $vendor has an upgraded version which doesn't do that?

both servers have the updated versions and latest patches.