So, I modified the code a bit and was able to make it work...sort of. It's taking the first sheet and importing the same data over and over again with the name of the workbook's worksheet.
Code:
Sub ImportAllSheets()
Dim wkb As Excel.Workbook
Dim sht As Excel.WorkSheet
Dim xl As Excel.Application
Dim strPathFile As String
strPathFile = "C:\Users\docs\file.xlsm"
Set xl = New Excel.Application
xl.Visible = True
Set wkb = xl.Workbooks.Open("C:\Users\docs\file.xlsm")
With wkb
For Each sht In .Worksheets
'DoCmd.TransferSpreadsheet sht.Name, HasFieldNames:=True
DoCmd.TransferSpreadsheet acImport, acSpreadsheetTypeExcel9, sht.Name, strPathFile, True
Next
End With
End Sub