[Lizard]

UTF-16 is for being smarter about handling some unicode characters, used in some foreign languages that have different alphabets than English. So it's probably not relevant here.

When you import into OmniPlan, you should get a little dialog with a two-column list. Make sure you choose the matching columns for each bit of OmniFocus data you want to put in your OmniPlan file. If any data from OmniFocus (such as Context) doesn't have a corresponding column in OmniPlan, you can choose "Import Custom Data" and OmniPlan will add a new column for it.