Using .Net 4.5 instead of 4.0 Problem

[necoinside]

Sorry if this is explained but I couldn't find any solution.

I use lcdsmartie over usb(via arduino) also installed .Net v4.5.1. Normal commands work well but other commands with use of dll file give error about .net framework and write dll could not opened.
If I uninstall .net 4.5.1 and install 4.0 it works perfectly but some progrmas I use needs latest framework so I have to update.

When I make change in LCDSmartie.exe.config as 4.5 or 4.5.1, than it program crashes completely and gives warning to install what I write as version (out of 4.0).

How can I solve this?

P.S.: Sorry for my English, greetings from Turkey.