First thing to note: The EZ-Flash IV does not support real save states. It does only support in-game saving on the GBA titles that contain a savegame chip. I would assume Medabots would have such a function (EDIT: indeed, Medabots contains a EEPROM v122 saver type).
Now that we clarified the terminology: Issues with in-game saving are usually caused by a bad dump or a (badly) save-patched ROM image. As of version 2.01 (iirc) of the EZFlash IV firmware, the card will properly handle games of any saver-type (SRAM, FLASH, EEPROM) on it's own without any required patches, in fact, patched save types can cause issues.
Here are the steps you need to take:
-Make sure your EZFlash IV card is on a recent firmware (2.01 - 2.05)
-Make sure youre using a clean, unpatched Medabots ROM image. Medabots - Metabee (USA) has an MD5 checksum of B186A9BA291A156C45640CB3C6B8A710 so make sure your ROM image matches this checksum.
-Do NOT use any software to patch the ROM image, whatsoever. Do NOT use EZ4Client, GBATA or anything else to modify the clean ROM. Just drop the clean ROM onto your SD card and run it.
-Try deleting the coresponding save file from the "SAVER" folder (and patch file from the PATCH folder - if it exists) on your SD card to rule out any damaged/wrong data here.
-You may also want to try a different SD Card.