HL2 Mod Not working

I was trying to get the free HL2 mod from Steam (Insurgency) but for some reason I keep getting this error message saying that I don't have the HL2 engine when I do (it came with portal).

Send a print screen to my email woodenplumbing@hotmail.co.uk I'll check to see if I can find out why.

Wow now it's just failing completely to download the mod. The button just doesn#t work

Have you only tried to do it today?

I tried it like a couple of weeks ago and I haven't found out how to do it. Then I deleted the mod cus it didn't work. Then I found out about this forum so I was just wondering if anyone knew how to fix it. It's fine I don't think I can even donwnload it lol.

Maybe you put the mod in the wrong game folder?

Well I haven't even downloaded the mod lol. I managed to download it a couple of weeks back but then it didnt work so i deleted it. Now the download button on Steam just doesn't respond at all. I've restarted and everything but I dunno what's up. It doesn't matter, I'll try and sort it out another time. But thanks for your suggestions.