If [INVOICE_NBR] is numeric ... try this:
DoCmd.OpenForm "FRM_INVOICE_MANAGEMENT", acNormal, , "[INVOICE_NBR] = " & Me("FK_INVOICENBR")
IF Text ... try this:
DoCmd.OpenForm "FRM_INVOICE_MANAGEMENT", acNormal, , "[INVOICE_NBR] = " & Chr(34) & Me("FK_INVOICENBR") & Chr(34)
mx