Why is my AppleMail sending blank or partial emails?

Question

My Apple mail is sending partial and blank messages, though it includes my automatic singature.
The problem is particularly present when I am sending a FWD or a Reply, but it isn't consistantly doing it... I'm not trying to send anything fancy, just text (Rich Text) and sometimes an attached PDF or WordDoc.
It doesn't always happen but started randomly on Monday (8/27). Sometims it happens when replying to an email sent from a phone—maybe this could part of an issue? I'm using a POP account (host is Dreamhost and webmail works on their end).
I use the email for work... HELP!

Answer 1

Could be many things, we should start with this...
"Try Disk Utility
1. Insert the Mac OS X Install disc, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu at top of the screen. (In Mac OS X 10.4 or later, you must select your language first.)
*Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.*
3. Click the First Aid tab.
4. Select your Mac OS X volume.
5. Click Repair Disk, (not Repair Permissions). Disk Utility checks and repairs the disk."
http://docs.info.apple.com/article.html?artnum=106214
Then try a Safe Boot, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, reboot when it completes.
(Safe boot may stay on the gray radian for a long time, let it go, it's trying to repair the Hard Drive.)
If perchance you can't find your install Disc, at least try it from the Safe Boot part onward.
If 10.7.0 or later...
Bootup holding CMD+r, or the Option/alt key to boot from the Restore partitirion & use Disk Utility from there to Repair the Disk, then Repair Permissions.