I would very much doubt that the problem is related with any Adobe product. Likely causes that come to mind at once: attachements blocked at receiving end, attachments size exceding maximum allowed.
You might want to try Adobe SendNow for sending your file. This will save you from the maximum size limit issue and even the file being blocked at the receiving end. Through this you will be able to upload the document to Acrobat.com and the recepient will get a link to download the document.