This really should be so very simple...
I have an asp.net master page which is working as expected. It includes some asp: tags without any problems.
The mast
Try this one
UPDATE: <link rel="stylesheet" type="text/css" href=<%="'css/main.css?v="+"34'"%> />
<link rel="stylesheet" type="text/css" href=<%="'css/main.css?v="+"34'"%> />