error as textures and missing files

i just bought gmod yesterday and i happend to find alot of errors in alot of server
for example:

i asked the other people in the server about that and they said everything was fine for them and they didnt see any errors

i logged into another server and saw

as u see alot of errors and pink/purple squares on glass and other staff at the background

is there any solution for this?
thx in advance

edit: i guess its because i dont have counter strike source
but i bought the game so i think i deserve the same gameplay as one who bought gmod and css