If you have the GBA sized EZ4 you can not have a compact (they were only released in the lite size).
As I said before, if when you first start the disk manager you see nothing but the EZ-Disk folder (the folder you open to acces your SD), then there is nothing burned to your NOR. If there is a file there, highlight it and press the select button then press A at the erase prompt... Actually, let's go all the way: Go to the file manager. Do not open the EZ-Disk folder, just stay on the first screen. Press start, then A. You just formatted your NOR.
If there is nothing there and you're still getting the error when trying to burn, your patched ROM has exceeded the size of the NOR (256Mb) in your EZ4. Did you patch this ROM yourself, or did it come patched? Do you have the unpatched Japanese version? The unpatched Japanese version should be 33,554,432 bytes (on your PC right click on the ROM and then select properties), this should fit in NOR as it is, this is the proper size of a fully dumped 256Mb game. The Fan Translation v1.1 version should be 33,554,432 bytes (the same as the Japanese version), if the version your are using is larger than that, that is why you are getting that error.
If you do not have the Japanese version, get it and patch it w/ patch from the
M3 Fan Translation page. After patching the ROM go back to my earlier post and start at Using EZ4 Client to send the ROM to your SD step.