can't uninstall and install nod32

hi there, i have nod32 trial version on my computer for a long time and i cant uninstall it, i've tried to install the newest trial version and still the same : ''A network error occured while attempting to read from the file C:\Windows\Installer\eav_nt32-env.msi'' and it's rolling back the action , i've tried to find the Installer folder in Windows but there is none (i've checked the hidden option as well), please help.