It might even be that another plugin altogether is breaking the theme before Jetpack even begins to load. The only way to determine exactly what’s happening is to complete troubleshooting (instructions below) to determine where the Javascript conflict actually lies.
To isolate which plugin(s) may be contributing to the trouble, deactivate all except WPtouch from within the WordPress Plugins area, clear your browser cache and local data then test.
If WPtouch functions well, you may then enable the rest of your plugins one at a time, repeating the process, until you can identify which is/are causing the problem.
You may choose to replace the conflicting plugin with another or upgrade to WPtouch Pro which has a feature that will allow you to disable the conflicting plugin within your mobile theme but leave your desktop theme intact.