"Extracting...this might take a while" message and download status bar running for 15 hours.

Having purchased Adobe Acrobat XI Pro Mac Download, and installed the program with Adobe Download Assistant, the program is loaded but the status bar has continued to run for 15 hours with a message underneath stating "Extracting...this might take a while".  Also, a warning message appeared during download stating "The following disk images couldn't be opened"; (Image) AcrobatPro_11_Web_W, (Reason) error -4960.  How do I complete this download?