FM Editor issue - Error extra teams in league

Hi All,

Not sure if this the correct place to post this.

I am trying to create an all Ireland Super League combining Rep of Ireland & Northern Ireland Leagues in to one nation,

I keep error message attached when trying to test it out. 

I thought it might be as I had originally start date similar to England but changed it back to Irish league start dates in Jan/ February.

Could someone help me with this please as im lost with this one.