When I install the 1.9.4 python sis file, the install fails midway with the "Unable to Install" error. Post this stage, no symbian applications can be installed or uninstalled on the device.
Device: Nokia 5800 XpressMusic. I came to the conclusion that Python for S60 is the source of the problem because I had to re-flash the device 2 days earlier with the same problem after installing python. This time, I installed all my usual applications and installed Python the last. Post this, no SIS file will install or uninstall.
Also, None of the symbian applications in the device are displayed in the Installed applications List.