If you are trying to import from iGTD to Omnifocus using the importer at my download page there should be no problem if your international settings specify "." as the decimal point separator.

In some countries, however, decimal numbers are traditionally separated by a comma, and if this is specified in System Preferences as your local default, the importer fails with an error of the kind:

"Il est impossible de rendre \"218538583.482917\" en type real."
or
"\"218538583.482917\" can not be converted to real"

The solution is to temporarily set your region (through System Preferences\International\Formats\Region) to an Anglo-Saxon location like USA or UK, run the importer, and then switch back to your own location.