Trying to install Win 7 on mid 2010 iMac running Mavericks but fail.??

Have a mid 2010, iMac running Mavericks. I am trying to install W 7 from DVD but always fail. Install goes all the way to last restart (?) and then reports that "boot mngr" is missing?? Looking at the boot camp disc of the installed W7 reports the "boot mngr" is there, or at least, one is there?? Had W 7 installed under Snow Leaperd with no problem but removed same because it was a piroted version, the new install is a legit version.