KCW Upload Error

Hai everyone,
i setup a custome page and embaded the KCW in my page, sometime i can upload a 145MB file smootly and sometime a same file it produce I/O error went upload.
Anybody know how to trace the problem.

My Print Screen:-
https://drive.google.com/file/d/0ByiTkbWQzKTGRllXdUo3Y1FRRzQ/edit?usp=sharing


update:-

this Error Showing:-

<‘xml’>
<‘result’>
<‘error’>
<‘code’>MISSING_MANDATORY_PARAMETER<’/code’>
<‘message’>Missing parameter “uploadTokenId”<’/message’>
<’/error’>
<’/result’>
<‘executionTime’>0.0016508102416992<’/executionTime’>
<’/xml’>

Thank

Nope no network problem occur. Maybe because of firewall / IPS . The server A will upload the video toward kaltura server and inbetween them there a firewall / IPS .Does firewall block can causethis thing.

Tq oferc.

ok will try n thank.