A couple of things could be fixed.
Firstly, the second chord in the progression, D/C# doesn't sound good, ESPECIALLY with strings, because of the b9 interval between the C# in the bass and the D in the treble. That chord can work if the bass is quickly passing through the C#, but since it's camped out there for a bit it doesn't sound right.
If you change the "D" in treble chord to an "E" it removes the offending dissonance and it creates a little inner-voice movement. Here's an MP3 that'll help you sort that out:
http://www.audiorecordingandservices.com/chord_fix.mp3 The string arrangement needs some work. It needs to "go somewhere". Why not start with just the low cellos/basses, maybe bring in a single note higg violin line and then finally get to the full texture in the chorus.
I'll also echo the comments of how compressed it sounds.