Hello,
since I just happened to experience same error, and this thread is not solved yet, it is worth to mention how I fixed it.
It occurs when specify
"."
as destination dir for
appeonfileservice.of_appeonupload (string source, string destination , boolean isrename, ref long errorcode)
From Appeon help in fact, it is
"The destination directory on the file server where the file is uploaded.The directory specified here is a relative path to the file directory specified in the appeonfileserver.xml configuration file."
I thought that destination "." could be just fine for root dir on the server. The file is uploaded, indeed it is viewable on the server, but its later download fails in "half-backed" error.
Then I changed destination dir from "." to empty string "" (credits to ZhaoKai), precisely from
appeonfileservice.of_appeonupload(is_filename, ".", False, il_rc)
to
appeonfileservice.of_appeonupload(is_filename, "", False, il_rc)
and the subsequent of_appeondownload is working!
Best,
.m