Hope you are doing well and sorry for the trouble. As described you are getting the error 507:507
This error means that Another Adobe Reader is running in the background. Please close the application and reboot the computer once and then try to open the PDF file and check.
You may also try to turn off the protected mode at startup (Windows Only) Go to Edit > Preferences > Uncheck 'Enable protected mode at startup' > Click OK and reboot the computer once.