means a certain smd files does not exist, if it doesnt then u must save your model as smd format, file -> export -> half-life smd -> save it in the directory you are compiling from. save as 18.smd, this would most likely be a reference smd becuase of the '18' most likely meaning android 18.
or you could change it in the qc file, open with note pad.
heres an example of the header of one:
// = comments
$modelname "C:\WINDOWS\Profiles\Smo\Desktop\???.mdl" // where u want model file 2 b saved 2, the file name etc
$cd "\WINDOWS\Profiles\Smo\Desktop\???" //the directory of the model files i.e. smd files
$cdtexture "\WINDOWS\Profiles\Smo\Desktop\models\???" // where the textures are
$cliptotextures
$scale 1.0 // size of the model.. just leave this
// 2 attachments
$attachment 0 "Bip01 R Blaster" 2.000000 1.500000 0.000000 // where sprites and beas origonate from
$attachment 1 "Bip01 L Blaster" 0.000000 0.000000 0.000000
// 3 bone controllers
$controller 0 "Bip01 Spine1" XR -30 30 //never mind about these
$controller 1 "Bip01 Spine2" XR -30 30
$controller 2 "Bip01 Spine3" XR -30 30
// 1 hit boxes
$hbox 1 "Bip01 Head" 0.090000 -3.660000 -3.000000 8.410000 5.090000 3.000000 //or these
$bodygroup body
{
studio "jetstorm" // this is where your would say '18' this states the name of the reference smd
thats about it
}