Journey Builder Validation Errors #MCExperts

A journey is outputting the below Validation error to all 5 emails in the Journey:

TriggeredSend Add/Update failure. An entry with the Name value already exists. TriggeredSendID: 00000000-0000-0000-0000-000000000000 Triggered Send Name: Email #1

Support said this was due to the 5 emails having too similar in name, Email #1, Email #1.1, Email #2, Email #2.1, etc...

I've renamed them and am trying to add them back in. I'm getting an error when trying to save the email activity and it won't let me select the "Done" button.

I've Previewed the emails against a DE and they are not erroring. Preview works. Here's the error in Journey Builder in the Email Activity Summary:

Review and fix these validation issues in your email.

• HTML_Body - Functions_Custom_Objects Error 1: Script SET Statement Invalid<br>An error occurred when attempting to resolve a script expression. See inner exception for detail. Script Expression: AKA MemberID: 100017703 JobID: 0 An unrecognized expression appears in a script block. Script Expression: AKA MemberID: 100017703 JobID: 0 <br>Invalid Content: <br>set @AKA = AKA
• TEXT_Body - Functions_Custom_Objects Error 1: Script SET Statement Invalid<br>An error occurred when attempting to resolve a script expression. See inner exception for detail. Script Expression: AKA MemberID: 100017703 JobID: 0 An unrecognized expression appears in a script block. Script Expression: AKA MemberID: 100017703 JobID: 0 <br>Invalid Content: <br>set @AKA = AKA

Ampscript in Email:

%%[ var @FirstName,@AKA set @FirstName = FirstName set @AKA = AKA ]%%

%%[if not empty(@AKA) then]%%%%=v(Propercase(@AKA))=%%%%[else]%%%%=v(Propercase(@FirstName))=%%%%[endif]%%,

I do have the Ampscript in a HTML block. Any thoughts?