Error 1856 message.

I uploaded 3 videos to Istockphotos.com in hope of eventually get some incoming from my videos. The 3 files started life as .mov files. I used converter software to convert them to .mp4.

Whether I try to play the raw .mov files - either from my computer, or from my camera - and try to play the converted .mp4 files. I get the following error message:

Error - 1856: and unknown error occurred

My operating system: Windows 7 Home Premium 64 bit

So far the Istock folks got one of the 3 videos to play and they've approved it (meaning they accepted it) but they said the other two would not play. I had converted all 3 to an .mp4 format per the instructions at their website. In their e-mail to me, they said I need to re-upload the files in a format that would play in Quicktime.

According to Apple's website, Quicktime 7 supports .mp4 and .mov

I don't know what else to do.

.

This is quite frustrating. Can someone please help me solve this isssue?

Thanks