Ok, issue with the umount was me. I wasn't putting a space between umount and /dev. Here's my next issue, I'm not sure i'm doing the dd correctly. Am I supposed to mount my first card before i copy it to my hard drive? Also when i use df -h it shows my cf card as sde1. Should my dd to my hard drive say sudo dd if=/dev/sde or sde1? and also for the dd to my new blank cf Should it say sudo dd of=/dev/sde or sde1? I ask because when i finally did the umount it wouldn't umount sde. It would say /dev/sde wasn't mounted. But when i did umount /dev/sde1 it unmounted. It's all a little confusing to me, but to restate, i'm just trying to make an exact copy of a cf card to another cf card, and somehow this machine knows i'm not using the original card. thanks.

You can check what was mounted using the command mount. You can umount only those filesystems. Usually that would be /dev/sde1, but sometimes /dev/sde can be valid too. You need to check it.
for dd:
if you want to copy the content of the device use if=/dev/sde, if you need only a partition use if=/dev/sde1 or similar. But again, it depends on how that card was formatted.

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OK, back to the beginning. These commands are correct.Nothing should be mounted on the CF card - nothing in /dev/sde[1-9]. You can't normally mount or unmount a device node (/dev/sde) - especially if partitions exist on it.
Personally I would alter the final command as follows - it forces the writes to the CF immediately rather than queuing them - saves worying about if it's finally finished or not.

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ok cool i'll give that one a try. The reason i was asking about the whole process again is that I'm making sure I copied to my hard drive correctly to begin with. Otherwise i'm basically trying different ways to copy a flawed copy to a blank card. If what i wrote seems like a good method (because i'm just following what i've seen) then i'll keep trying to figure out what's wrong with my final steps. I'm thinking about buying another card reader so i can skip the middle step and go card to card, if that would eliminate a possibly erroneous step...anyone let me know if that makes sense. Thanks

no, that would not eliminate your problem. Your original problem was you removed the device before the writing process was completed. You can force to complete it by:
1. using the flag suggested by syg00: oflag=sync
2. manually umount that device (or eject it)
3. execute the command sync (as root).
(obviously wait as long as the commands completed and afterward you can remove the card.

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Hey, not sure if that's a list to follow in order or 3 different options. I'm doing the first step right now in my ubuntu virtual machine. I'm also thinking maybe I took out the card prematurely when i copied it to my hard drive because i just waited for the bar to stop blinking and for it to say virtualmachin:~$ and unplugged it. Right now that machine is not in use i can grab that cf and re-copy it to my hard drive again just to be safe. i haven't read about the flag=sync yet, so i'll ask, if i do copy the good card again should my command look like this?

sudo dd if=/dev/sde of=/home/folder/cfcard oflag=sync

Yes.

pan64 was giving you options. Pick one.

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that is not flag, but oflag. All the 3 options make the same thing, forces to write the data from the buffers onto the device (flush buffers).
sudo dd if=/dev/sde of=/home/folder/cfcard oflag=sync
is ok.

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Before you use dd to copy the device, use df only to identify the two device names.

THEN dismount both (though dismounting the source shouldn't make a difference) and use dd to copy.

The problem with using dd to copy a device to a second device while that second device is mounted is that the system holds filesystem information in memory (which may be empty). ejecting/dismounting will corrupt the result of the copy and the final device may be totally unusable.

my god, yes, you should umount before dd, so option 2 is not ok.

ok, i think i follow what was just said, but to be sure i'm going to state what i did. I used optioned 1. I never used df since the system keeps calling my cf "sde". I entered the command

sudo dd if=/dev/sde of=/home/folder/cfcard oflag=sync

then just pulled out the cf card since syg00 said "Personally I would alter the final command as follows - it forces the writes to the CF immediately rather than queuing them - saves worying about if it's finally finished or not.

and now i plan to use the command

sudo dd if=/home/folder/cfcard of=/dev/sde oflag=sync

to copy to my blank card. Though i've been meaning to ask since i only have a couple of spare cf cards. Was there some sort of formatting i needed to do before i copy to a card if there was already something on it? I haven't because i thought dd just copies over whatever was on the card. Thanks for all the patience, i'm no where close to a programmer and i'm learning everything i need to know just to accomplish this task. So feel free to talk to me like a child, because the language goes over my head real quick. Thanks

dd will destroy anything on that card, so you do not need to format/prepare.

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Maybe it simply checks the serial number of the card?

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You could try copying two different cards to separate disk files & do a md5 check to see if they are same or different.
You could also try the same with your newly created card to check that you have a match.

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It depends on how the licensing works. It is likely that the two cards have different license keys.

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