If you have a disk image of your Windows partition, you could try re-imaging it with that. Or perhaps if you can, load the Windows installer and use it to repair. Basically it's no longer detecting your "BOOTCAMP" partition as a bootable partition.
In future, if you have something like VMware Fusion, you could use it to make a snapshot of your Windows install. Then it's easy to port to another computer. It's also easier to restore a b0rked install.