Look at you Query and the relationships.  You may have created the query such that it's not updateable.

See the Not Updateable video.

Otherwise check that your properties for the form allow edits and additions.

Scott,
I'm not sure this is the issue.  My InboundPersonnelT has a new row in the table and I have created Primary and Foreign keys. My form is based on a query (InboundPersonnelQ) where I'm trying new personnel basic info (to my InboundPersonnelT) as well as add the mailing work and home addresses (via a subform to WorkMailingAddressT and HomeMailingAddressT, respectively), just like Mr. Roth has taught. Also, all the tables in the query have a "new" row at the bottom of their table. But still in the DataEntryF there is no option to add a new record via the new form. (The arrow the bottom with a star next to it, is grayed out.)  This leads me to think there's something wrong with the query relationships, but I cannot seem to see it.  
Your thoughts?
--Kent J.

Check the record source for your DataEntryF.  If that is grayed out that is likely your issue.

I would probably help us to see what your working with.
Would you please post a pic or two in design mode of the form in question? Include the properties.
Also of your query.
If you post a form view then be sure to black out any sensitive data as needed.

See the Snip & Sketch if your now sure how to do that.

When you start typing to create the record the New Record button should automatically become enabled.

When I try to add a new record, I get an error that says "You cannot add or change a record because a related record is required in WorkActualAddressT."  I have a subform added to my form that covers work addresses. This error leads me to think it's a relationship issue. But again, I cannot seem to figure out which relationship is causing the hiccup.  I'll post a picture later tonight of the Query and form in design mode, which will take me awhile to sanitize.  --Kent J.

You can see from the files I just uploaded, I'm trying to create a Data Entry form with two subforms in it.  I'm interested in your ideas.  The form is based on a query with outer joins.  I can start to create a new file, but then it gives me the error "You cannot add or change a record because a related record is required in WorkActualAddressT."  
--Kent J.

First thing I see is in your Tables that are just screaming out  to me.

Make a copy of your DB  (Backup)

You have a blank field name in the InboundPersonnelT and in the CurrentOI-GIPersonnelT.
Unless you have blanked (censored) those out for some reason, that should not be possible.  Fix that first. Then compact and repair your database.
This might be an indication that your db is corrupted.

Split form is the #3 topic on the Evil Access Stuff
They are notorious for causing issues.  I highly recommend going a different route.

See if things work after that and come back.

Scott, I do have a fieldname in the blank parts, which I've censored for privacy issues, in both the query and the table.  
I've also compacted and repaired the database.  No joy.
Per your suggestion, I've deleted the split form entirely from the main form to see if I can get it to work with just the Arrival details subform.  Now I get a new error: "Cannot add record(s); join key of table "CurrentOI-GIPersonnelT" not in recordset."  
I'm thinking I may have to create the query from scratch and reassign it as the new control source.  
Thoughts?

I have cracked the code.  I now see why Split Forms are so bad. When I messed with and deleted the Split Form, Access deleted e WorkAddressID (my foreign key) in my query.  [Sigh.] So, I've added back in the foreign keys to the query and gone the route of using relational combo boxes for the work addresses.  Next step...use DLOOKUP to show in my form the second column of the addresses.  That's putting the expert courses to work.... ;-p
Cheers!
Kent J.

Split forms are evil.