Vista - ADO connection to excel file - using MS office 2003

hello,
I'm using VB6 with the below connection string to connect to excel files to
read data.

Set oConn = New ADODB.Connection
oConn.Open "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=" & sSourceData & ";" & _
"Extended Properties=""Excel 8.0;HDR=NO;IMEX=1;"""

I CAN connect to any of my created file on my pc and read data from it
however i can't and have a problem with reading external excel files, I mean
a files created and send to us from people working from outside of company.
Then any attempt to connect to such files fails with the following reason
'External table is not in the expected format'.

If I start to debbug my component to read the excel file data and leave the
file opened then the connection happens fine.

If I manually copy the excel data and paste them to a new created file on my
pc then the connection happens fine.

I have MS office excel verision is 2003 installed on my pc
If I try to save the original file as MS office 2003 verison or any other
format it does not help and fails with the same error message

First, I didn't know what version of MS Office Excel the external people
have. I thought then they might use new MS office 2007 so I tried to install
new driver from the following page
:http://www.microsoft.com/downloads/d...displaylang=en

using then a new connection string as it's following:

' oConn.Open "Provider=Microsoft.ACE.OLEDB.12.0;" & _
' "Data Source=" & sSourceData & ";" & _
' "Extended Properties=""Excel 8.0;HDR=YES;IMEX=1;"""

changing the extented properties from Excel 8.0 to 12.0 to 5.0 -> no succcess

Now I was ensured they use MS Office 2003 too to create the excel files.

So here I am trying to find a help, solution as I havent found any
resolution via other posts.
any help, thoughts would be much appreciated.

Lukas