Adobe Acrobat 9 Error 1606 can arise during the installation of this software and even it can occur while Adobe software is running in the system. The main reason which causes this error to occur is the windows registry files goes corrupted. So as to fix this error you can try the following steps:
• Conduct the full system scan of your computer
• Try to remove all the system junk files by deleting cache data
• You can also update the device driver of your system
• repair the registry files which are associated with error 1606
• Uninstall and then reinstall Adobe Acrobat 9
Even after executing these steps if your problem is not resolved then you have contact acrobat reader helpline number where experts are present at all time to help the clients in eradicating the error.

Read more - acrobat reader tech support number