hi I've got the solution.
when u click on download masterservers.vdf on Setti it opens up some wierd stuff right?
copy the writing and paste it in ur masterserver.vdf in the cs directory under platform/config
E:\CS Source\Counter-Strike Source\platform\config) by right clicking the masterserver.vdf and clicking edit.
replace the text in it.
save it as it asks and then change the file name from masterservers.vdf.txt to masterservers.vdf