Update Manager/Software Centre not working (12.04 LTS)

Update Manager/Software Centre not working (12.04 LTS)

I restarted my computer and a little red circle with a horizontal white
line appeared. I clicked on it and it asked me to show updates, so I did
that. Next, it says this:
"An unresolvable problem occurred while initializing the package information.
Please report this bug against the 'update-manager' package and include
the following error message:
'E:Type 'ain' is not known on line 3 in source list
/etc/apt/sources.list.d/ehoover-compholio-precise.list, E:The list of
sources could not be read., E:The package lists or status file could not
be parsed or opened.'"
Can anyone please help me?