Error in Synaptic- Application gone missing

[angrez]

First of all I am relatively new to Linux, so forgive me if I'm 'slow' or if I'm using the wrong terms or words. This is what happened...

-I wanted to use Gnomad2 so i could sync my ZVM...so I installed it from Synaptic
-The installation was successful, I saw that Gnomad 2 was available now under Sound and Video
-But before I could click to open, I accidentally hit my machine's reset button.
-My computer restarted and had errors, Not a problem as Ubuntu fixed all errors and I managed to login again.
-But this time I could not find Gnomad2 anyway, I typed gnomad2 in the terminal, it couldn't find it
- So i thought I will reinstall it again from Synaptic but the problem is Synaptic says it is already installed and I can't remove it or reinstall it

This is the error that I'm geting in Synaptic

dpkg: failed to open package into file '/var/lib/dpkg/available' for reading: No such file or directory
E: Sub-process /usr/bin/dpkg returned an error code (2)
A package failed to install. Trying to recover:

Really need your help as I can't live without music. Thanks