Ok if you are on 3.41 like the member said above and trying to jailbreak with the 3.55 jailbreak it is not going to work.
So download this files which is the Sony 3.55 OFW.
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Then on a USB make a folder "PS3" and inside of that "UPDATE"
once the file is donwloaded drag it into the "UPDATE" folder.
Now plug the USB into the ps3 and go
-> SYSTEM UPDATE
-> UPDATE VIA USB MEDIA DEVICE
-> ACCEPT THE TERMS AND CONDITIONS STUFF.
Now your ps3 is 3.55 download the 3.55 jailbreak CFW
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delete the 3.55 OFW from that folder and put the 3.55 Jailbreak Firmware
Do the same thing. SYSTEM UPDATE - USB MEDIA DEVICE
NOW ACCEPT and MAKE SURE YOU CHECK THE BOX [] TURN OFF PS3 AUTOMATICALLY and then turn it on manually and your ps3 is now jailbroken.