>Cetin,
>
>Yes, I am passing the full path and filename (but no file extension). This same code has worked fine before, and still works fine on the clients that are using Excel 2003 and earlier.
>
>I can open a file from my local drive via automation just file (even the same files). I can also open the file on the the network share interactively from within Excel itself (no automation). However, when I try to open from the network drive via the automation object I begin to get the error. I've tried mapped drive letter, unc path, filename with and without the extension. I believe it is some kind of security or "trust" setting in the new version, but I can not seem to find exactly what it is or how to set it to what I need. (I was able to record a macro and open the files using the macros from with Excel itself.)
>
>I seem to be able to open Word documents just fine from the same location using Word 2007.
>
>Any ideas?

No, not exactly. Just reminds me of IE7's weird security defaults (if source is not local computer then not trusted).
Cetin