Having a problem " signature varification failed"

[Alienolas]

So i dont know if theres already a forum for this and im sorry if there is but i have a captivate and i am trying to install my first custom rom, i downloaded the rom and placed it in sd card as update.zip then i bbooted into revcovery mode tthen clicked reinstall packages. The little green bar gets about a third of the way untill the following error comes up signature varification failed, i tryed a nice few times and no luck i even looked it up on google but nothing. I would be grateful if someone could help thanks

 

[konazxiii]

Read this carefully- it has everything you need to move forward.
[RECOVERY] 3e Recovery Modded w/ No Verification - xda-developers
If you have questions, post them here- you'll probably get a quicker response.

And put XDA in your bookmarks- you most certainly will be back. It's addicting.

Also, out of curiosity, what ROM are you looking to install?

 

[Alienolas]

Read this carefully- it has everything you need to move forward.
[RECOVERY] 3e Recovery Modded w/ No Verification - xda-developers
If you have questions, post them here- you'll probably get a quicker response.

And put XDA in your bookmarks- you most certainly will be back. It's addicting.

Also, out of curiosity, what ROM are you looking to install?

I tried to install many but the first one i tried was cognition i think, i dont even know if i will like it cause i never see any photos of any roms. I really want one that mimics touchwiz 4.0 but had not luck finding it ...sad face...

 

[konazxiii]

Friendly advice: Read a lot first, always back up to your computer, and go with a Froyo (2.2.x) ROM first.

Gingerbread is something you may want to work up to due to the need to flash new bootloaders.

GB ROMs are where you're (mostly) going to find TW4...it's pretty buggy right now, so you aren't missing much.