Error Code 4 is generic message generated either from your computer or your internet browser and not from 3Play Media. The error message typically appears when attempting to upload content to your 3Play Media project and indicates that your computer system cannot open the file. If you have a lot of other files and applications (especially web-based apps) open then close out these applications and try uploading the files again.
It may also be that there is a firewall at your office preventing you from being able to upload content for transcription, captioning, and translation services. If the issue persists please contact a member of your IT personnel to investigate if this could be problem preventing successful uploads. Once the firewall is lifted, Error Code 4 should no longer interfere with the upload process.