[AccessD] Tabbing to Another control

I have a form called frmClient.
On it is a tab called tabClient.
On tabClient is a subform called sfrClientRevision
On sfrClientRevision is a tab called tabRevision with two pages - 
pgeSaving and pgeBudget

On pgeSaving is a subform called sfrClientInvestment
On sfrClientInvestment is a field called cboInvestmentType

On pgeBudget is a subform called sfrClientBudget
On sfrClientBudget is a tab called tabCashFlow
On tabCashFlow is a page called pgeSummary
On pgeSummary is a field called txtpgeSummaryLast

What I would like to do is this: When txtpgeSummaryLast is tabbed 
into, then the focus automatically moves to cboInvestmentType.

What I have tried on the OnEnter event of txtpgeSummaryLast is this:

     DoCmd.GoToControl "sfrClientRevision"
     DoCmd.GoToControl "tabRevision"     <-- Error here
     DoCmd.GoToPage "pgeSaving"
     DoCmd.GoToControl "sfrClientInvestment"
     DoCmd.GoToControl "cboInvestmentType"

The error message I get is No 2109: There is no field named 
"tabRevision" in the current record.

I have also tried:

     Forms!frmClient.SetFocus
     Forms!frmClient!sfrClientRevision.SetFocus
     Forms!frmClient!sfrClientRevision.Forms!sfrClientInvestment.SetFocus 
<-- Error here

The error message I get is No 438: Object doesn't support this 
property or method.

How can I get from txtpgeSummaryLast to cboInvestmentType?