This works for me. But you may need to modify it if you are not on Excel 2010.
Suggest you test this as follows, just to prove it will work for you before trying it out on your proper data.
If you name all the macros and the files as per my suggestions, it will make it easier for me to help if, for any reason, this fails to work for you.

1 Create a test Excel file with one simple macro in it like:

Sub ExcelMacro()
Range("A1").Value = Range("A1").Value + 1
ActiveWorkbook.Save
End Sub
2 Save the file as macro enabled with name ExcelFile.xlsm
3 Close the file and then open it again enabling macros (should only need to do this once - depending on your settings you may not even need to do it at all)
4 Add the following macro which it will run automatically the file opens next time
Private Sub Workbook_Open()
Dim answer As Integer
answer = MsgBox("Run Macro from Word?", vbYesNo + vbQuestion, "You can say NO")
If answer = vbYes Then
Application.Run "ExcelMacro"
Else
 'do nothing
End If
End Sub
This image shows you where it needs to go.
OnOpen.jpg
5 Save the file and see a message box pop up when you open it again. Click on yes to run the macro.
6 Close the file
7 Create test Word File (saving it as a macro enabled document with name WordFile) and create the following macro - amending the Path to where Excel.exe is on your system and File to match the folder that ExcelFile.xlsm was saved to
Sub WordMacro()
Dim x As Variant
Dim Path As String
Dim File As String
Path = "C:\Program Files (x86)\Microsoft Office\Office14\excel.exe"
File = "D:\Documents\VBAForum\ExcelFile.xlsm"
 x = Shell(Path + " " + File, vbNormalFocus)
End Sub
8 Run the macro and let me know if it worked or not and then I will help you make the real macro work.