The description is spot on with the .NET 4.5 issues you refer to - are you absolutely sure .NET 4.5 is not installed on the server?
Note that .NET 4.5 just need to be installed on the server for this problem to appear - it will change functionality on sites running 4.0 immediately - no changes to web.config or apppools are needed.
Most likely a fix would be to upgrade to 3.2 and then apply the latest patch available in "System | Packages | Available Packages | Composite.Updates". Or while youy are at it, upgrade to the latest release. See https://compositec1.codeplex.com/discussions/353796 for manual upgrade steps - or get our automated/supported upgrade service at http://www.composite.net/Plans-and-Pricing
Note that .NET 4.5 just need to be installed on the server for this problem to appear - it will change functionality on sites running 4.0 immediately - no changes to web.config or apppools are needed.
Most likely a fix would be to upgrade to 3.2 and then apply the latest patch available in "System | Packages | Available Packages | Composite.Updates". Or while youy are at it, upgrade to the latest release. See https://compositec1.codeplex.com/discussions/353796 for manual upgrade steps - or get our automated/supported upgrade service at http://www.composite.net/Plans-and-Pricing