Ah, ok got it. I guess that's why this problem is so frustrating is becuase of it's vagueness. The seemingly most simple task does not work as intended. Host a pdf on Sharepoint--> try to access said .pdf--> get error.
My env:
Sharepoint 2010
Windows 7 64-bit/32-bit & Windows 2003 TS clients
IE 8,9, & 10
Adobe Reader 11.0.2(3 & 4)
Adobe Acrobat Pro 10 (10.1.7)