I'm thinking that the combination of these two messages means you haven't
activated your ereader and set its clock.
Generally, errors that refer to ADEPT are related to a problem with your
computer's clock. You should check the date, time zone and time of your
computer's clock, and make sure that it's correct. If it is, then your
ereader's settings aren't set yet.
The second message relates to your ereader. You didn't say what that
ereader is, so I can't talk about specifics. General process is to to to
the site that is linked to you ereader and register it with that site (Nook
to B&N, SONY to SONY, etc.). Once you've done that, then ADE will be able
to authenticate your ereader and work with it.
There's also a chance that your ereader isn't supported by ADE. If you go
to ADE's Help page, you'll find a link to supported devices on the right
hand side, at the bottom of the first group. If your ereader isn't
supported (iPad's aren't, for example), then you'll have to use another
etext management software, not ADE.
Hope this helps!
My ereader is cooler and ADE does support it
The device is reporting bad values to Adobe. Try to reset the device to see if that helps. If not, some people have reported luck deleting the .adobe-digital-editions folder on the device, and then resetting the device.