Um. That doesn't look right at all:
<project defaulttargets="Build">
xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
Has a tag close ">" on the first line, and on the second.
So does the next bit:
<import project="<br" mode="hold" /> "C:\Program Files\MSBuild\MSBuildCommunityTasks\MSBuild.Community.Tasks.Targets"/>
That isn't valid XML at all.
What I would suggest is that you get Visual Studio to create you a basic .proj file and edit that instead of trying to manually create it, since if that is your whole file, there is a whole lot missing - which would explain why it can't be loaded.