If I go into my bin folder and run the apps manually they will run for css but not for half-life 2. Whenever i attempt to do anything with half-life 2 with the SDK stuff it gives me that error. I tried re-installed but that didn't help. Hopefully someone on the steam boards can help me once they finally authorize my account *sigh*
I got it working had to delete it using the steam delete local files option and deleting the files left over in my steam folder afterwards then re-downloaded it. did that three times and it finallyworked. Have fun and good luck