Hi Radhamani,
1. Make sure you have the latest Personas Client note from here:
SAP Screen Personas - How to configure the system (troubleshooting FAQ)
2. In the same blog above, I have listed a kernel note which is 1913055. This note is for kernel to accept file upload/dpwnload request from Personas.
(But this note is only applicable for kernel patch 200 and above).
File upload/download will work is you take care of the above 2 things.
Best Regards,
Sushant