If you installed from the Web App Gallery, that is an older version of mojoPortal as we have skipped a few versions in submitting to the Gallery. 126.96.36.199 has never been submitted.
If you are using our platform installer feed then you should have version 188.8.131.52 not 184.108.40.206
In any case I would try upgrading to the latest version currently 220.127.116.11.
I don't know of anything other than the missing control declaration that could cause that error and the releases do have the declaration, but still updating to the latest release is the best advice I have for this problem at the moment.