Hello,
You may be running in to an issue caused by Internet Explorer.
Try this:
Internet Explorer, Tools, Internet Option, Security, Custom.
Find the "Include local directory path when uploading files to a server"
Click on "Enable"
Upload a new assett and see if the problem persists.
Also here is a link to the Compatibility Information for DMS.
http://www.cisco.com/en/US/docs/video/digital_media_systems/dmscompat3.html
As a general rule of thumb use:
Firefox for the DMM, SNS, DMP, MXE
Internet Explorer for the TCS, AS series encoders.
Best Regards,
Keith