Searching the DLS for 'Greg Cash' with a space between his first name and surname won't yield any results though Patchy - you have to type it as 'gregcash'. But I just checked for 'C17' and found it easily enough anyway, and also realized the cause of Spider's problem.
Basically Spider, the brown QR C17 class (which there are several different number versions) is actually 09/10 content, where as you seem to only have 06 as your latest version of Trainz, which explains why you weren't able to find it on the DLS (the DLS will only display content for your current version of Trainz and those below - it will not list any content for later versions you haven't registered.).
Therefore, the only way to use this version of the C17 is to upgrade Trainz to either 2009 or 2010, then you should be able to download it from the DLS and install it.
