Problem creating new textures

Just followed the tutorial for creating materials from tga files, but
every time I drag the file into the vtex program it says it "can't open
C:\Program
Files\Valve\Steam\SteamApps\<username>\sourcesdk\sdkcontent\materialsrc\customtex\base_floor2.vtf"
file and won't go any further. Bear in mind I'm using the sdkcontent
folder instead of the counter-strike folder, but it should work all the
same. Any ideas why?

"Can't open *.vtf"? Are you dragging a .TGA onto the VTEX program? Please copy and paste what it says in the window fully (right click, "select all", press CTRL+C). Here is an example of it going right when I drag something from the materialsrc folder onto VTEX (from one window into another)

input file: C:/Steam/SteamApps/leperous/sourcesdk/sdkcontent/materialsrc/SDK/bump_height
output directory: C:/Steam/SteamApps/leperous/sourcesdk/sdkcontent/materials/SDK

config file C:/Steam/SteamApps/leperous/sourcesdk/sdkcontent/materialsrc/SDK/bump_height.txt not present, making an empty one
Hit a key to continue

input file: C:/Program Files/Valve/Steam/SteamApps/loco161104/sourcesdk/sdkconte<br style="font-style: italic;">
nt/materialsrc/customtex/base_floor2<br style="font-style: italic;">
output directory: C:/Program Files/Valve/Steam/SteamApps/loco161104/sourcesdk/sd<br style="font-style: italic;">
kcontent/materials/customtex<br style="font-style: italic;">
config file C:/Program Files/Valve/Steam/SteamApps/loco161104/sourcesdk/sdkconte<br style="font-style: italic;">
nt/materialsrc/customtex/base_floor2.txt not present, making an empty one<br style="font-style: italic;">
Can't open: C:/Program Files/Valve/Steam/SteamApps/loco161104/sourcesdk/sdkconte<br style="font-style: italic;">
nt/materials/customtex/base_floor2.vtf<br style="font-style: italic;">
Hit a key to continue

That's the full thing. No file is created (except the text file), and voila! No texture/material.

Create the directory customtex in your materials directory and it should work. I just tested something similar, and it seems VTEX can't create directories.

Will test in a minute - I've just had to re-install Windows so it'll be a while before I can do anything yet! Thanks for the help.