The email from Bill Betterman seeking help to get money out of Iraq is a typical example of the advance-fee-fraud scheme. The advance-fee fraud scheme has been made popular by the Nigerian 419 scam modification and finds its roots in the Spanish Prisoner scheme of the late 1800s.
Some of the frequent variants to advance-fee fraud schemes that we see in the email example you provided:
Frequent causes of victim’s financial losses:
1) The Scammer will make multiple requests that the victim wire money to offender to cover a number of supposed transaction expenses (e.g. bribes to local officials or customs agents in the offender's locale, wire transfer fees associated with wiring money to victim, and handling fees).
2) The scammer will ask the victim to wire money as a sign of good faith so the scammer knows he can trust the victim with the money that he supposedly will wire him/her.
The military variant appeals to the support U.S. citizens hold for our enlisted servicemen and servicewomen. Thus, criminals look to take advantage of this support and the trust we place in our military personnel. We have also seen variations of the advance-fee fraud scheme that take advantage of the generous nature of U.S. citizens. These include schemes with the following charitable themes: AIDS, cancer, and Hurricane Katrina). There have also been variants that take advantage of the trust a person places in romantic partners/interests. The offender, typically a male, lures weak women through online dating sites and farms the relationship (online) to the point at which the criminal begins asking the victim for money. The money will allegedly pay for the offender’s travel expenses to see the victim.