security ring is broken? what does this mean?

I used to remote into my work network using a Citrix receiver plug-in, and it suddenly quit loading. My IT people told me my security ring was broken, and that someone at an Apple store had to fix it. Is this accurate? What does this mean? My computer will not allow me to reinstall the Citrix plug-in, saying it is from an "unidentified developer". Now I'm stuck. What can I do?