Hi,
what is the version of your installed .NET framework and your target platform?
I have tested the VB versions of Rebex sample projects that target target standard .NET 4.0 (samples from the "vs2012-net-4.0" folder) and .NET 4.5 version (e.g. samples from the "vs2012-net-4.5" folder) and they atually both work and compile fine.
If you still experience the problem, please share more details with us(your target platform, your .NET version, the sample that does not compile) so that we can look into this issue.