Three things to try...
- Using Windows Explorer navigate to C:\Program Files (x86)\Adobe\Reader 11.0\Reader, then double-click on Eula.exe and accept the license agreement
- Can you open Adobe Reader by itself? If so, try disabling Protected Mode [Edit | Preferences | Security (Enhanced)].
- It could even be a malware issue; see http://helpx.adobe.com/acrobat/kb/reader-core-dll-error.html