Have you updated to AOL 9.0? I use Incredimail occasionally which worked fine with AOL 8.0. Now, although my messages from Incredimail are sent, they do not arrive at my sister's AOL email address. They will at her MSN address, however.
I wondered if AOL's advanced Spam Filtering was gobling them up or some other change associated with AOL 9.0.
Suggest you go on AOL live help and post your question there. The only trouble is they tend to be busier in the evening than during the day so you may have to be patient.