Can't Send Attachments Using Exchange Account

For some reason I can't send attachments using my Exchange account on my iPhone. Pictures, Word docs, Excel Docs, doesn't matter. They just get stuck in my out box and I get the following message, "Cannot Send Mail - An error occurred while delivering this message." I can receive attachments just fine, but cannot send or forward them. If I use any of the other email accounts on my phone, it works fine. The Exchange account is the only issue. Is this some limitation with Exchange on an iPhone or something? Anyone ever have the same problem as was able to fix it? Thanks!