When I run my application directly from the mobile device this throws me this error, I check in my project and the assembly if it is there with the version that indicates the error that is 3.5.0.0 
what would be the solution for this error that is being presented to me
I think you're missing a reference to the assembly you're asking for. Use the MSDN link that tells you the steps to do what I tell you. If you do not get it, we'll continue with something else.
On the device you have to install the .net compact framework
.NET Compact Framework 3.5 Redistributable
you have to have the .net framework on the device to work, it does not work if you have it on the pc where you develop