dknutson,
The error indicates that your project is configured to work on Java 6, but your MyEclipse 2014 doesn’t include that version of JRE System Library. You can overcome this warning by either including JRE 6 system library in MyEclipse or use workspace default JRE for your project.
Including JRE 6 library in MyEclipse :
-> Navigate to Window > Preferences > Java > Installed JREs > Click on Add > Select Standard VM and click Next > Click on Directory and browse for JDK 1.6 directory > Click Finish > Click Ok.
Using workspace default JRE :
-> Right click on the project and select Properties > Java Build Path > Libraries tab > Select JRE System Library [JavaSE 1.6] > Click Edit > Select Workspace Default JRE > Click Finish > Click Ok.
-> If your workspace default JRE is Java 7 (the one that is checked/selected under Window > Preferences > Java > Installed JREs), then make sure that the Java compliance level is set to 1.7 for your project. (Right click on the project and select Properties > Java Compiler > select 1.7 for the Complier compliance level > Click Ok)
Let us know how it works for you.