OK, so I have been reading through these boards and at first, could not open wav attachments sent from my voicemail system, but after reading here, found out to upgrade the OS on my 8130, so I upgraded to the newest, linked right at the top of the page.
Now, it gives me the option to open the WAV attachment, but then it just brings up a screen that shows VOICE.WAV (name of the attachment) and doesnt play it.