Hi DK;

  Can you tell us ...

1. What location are you trying to download the image file to?
2. What PowerServer version are you using?
3. What mobile device are you using?
4. What mobile O/S & version is involved?

Regards ... Chris

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