String fix for Bug 347954 - Running the NSIS installer as normal user (restricted group) or without enough free space available makes it silently fail. r=beltzner

browser/locales/en-US/installer/custom.properties

@@ -70,7 +70,7 @@ ICONS_DESKTOP=On my &Desktop
 ICONS_STARTMENU=In my &Start Menu Programs folder
 ICONS_QUICKLAUNCH=In my &Quick Launch bar
 WARN_WRITE_ACCESS=You don't have access to write to the installation directory.\n\nClick OK to select a different directory.
-WARN_DISK_SPACE=You don't have sufficient disk space to install to this location.\n\nClick OK to select a different drive.
+WARN_DISK_SPACE=You don't have sufficient disk space to install to this location.\n\nClick OK to select a different location.
 
 STATUS_INSTALL_APP=Installing ${BrandShortName}...
 STATUS_INSTALL_LANG=Installing Language Files (${AB_CD})...