[geoschmo]

You have to make sure you load population on the ship before it leaves your homeworld. Most likely you are hitting the colonoze button within your home system, but when colonizing out of your system you are hitting the warp button to move to that system and then the colonize button. the colonize button will automatically load pop and then move to the planet. If you are going to use the move button or warp you have to manually load pop before you do.