Hi,
The Linux included in SDK v7 is version 3.12 and uses zImage + device trees, instead of uImage to boot. The linux "create-sdcard.sh" script creates two partitions: "boot" and "rootfs". The "boot" partition only contains the MLO and u-boot.img binaries. The zImage and device tree binaries are located inside the /boot folder under the "rootfs" partition. This is how you should partition your SD card.
I notice that the version of your U-Boot is 2013.04, which isn't the one included in SDK v7 (U-Boot 2013.10). Please check why. Perhaps this is the reason why your U-Boot is trying to look for an uImage instead of a zImage.
Please note, that booting using uImage is also possible - you just need to alter the U-Boot environment variables. Using an older U-Boot, this may already be the case - check the "bootcmd" variable.
Best regards,
Miroslav