It could be the server it checks for updates isn't responding in the manner 0.955 expects. Anyway, all the version check does is tell you to get the new one; it doesn't do the patching for you. You can download the latest version (1.011) from various sites--
this page on TaleWorlds links to several popular mirrors. Note that the upgrade patch only works for 1.0 or newer, so you will need to download the full installer instead.
0.95x/0.960 mods are not compatible with 1.x; to use both at the same time, make a copy of the installation folder or change the path in the installer.