What version of android are you running?
Its a google issue. They havent approved all of the Android OS's for the protected apps section of the market.
Sling you guys are losing a lot of money by not offering this some other way than the Market. Most people using slingboxes are tech savy and are running the latest and greatest Android version which can't access all the apps within the market.
I am also frustrated that I can't download it (or see it) on market place from the PC or from the android phone. Slingmedia will loose out as I already bought a copy for my WindowsMobile phone and will just use that.
Big failure on Slingmedia; screw them for not having a solution and sending me wrong information via email!
I just found this info from Android Market: http://market.android.com/support/bin/answer.py?answer=138294
Some countries have yet to support Paid Apps function from Android Market, therefore unless Sling Media allows another method (not via Android Market) to pay for its mobile player, users from those "unsupported" countries simply cannot get the Android mobile player.
There's actually a couple reasons why the Slingplayer Mobile (SPM) for Android isn't showing up in the Google Andriod Market Place. This is because SPM is marked as a paid, copy-protected application. Google uses filters in the Android Mariet to manage access based on sanctioned country, rom, and phone combinations.
As the link in your message shown, only a small subset of countries have the ability to buy Andriod applications. Despite that list, New Zealand and Japan aren't able to purchase the application either. The country is determined by the SIM in your mobile device not by physical location. So, you could get around Google's filter by using a pre-paid SIM from one of the supported country.
The other filter is due to the application being copy protected. Google will govern your access based on the "/system/build.prop" file. If it is sanctioned, then Google will have its fingerprint saved it in their database. This can prevent certain phone/ROM combination and rooted access from seeing any copy-protected applications within the Andriod Market.
The following link best describes the issue and possible workarounds (http://androidforums.com/samsung-galaxy-spica/98024-protected-app-market-fix-tutorial-build-prop.html).