If a pod complains about not finding /Developer, you may need to update your location for Xcode. You can check which version your computer thinks is the latest by running xcode-select -p if it's not what you expect:
# Note that you are referencing the Xcode bundle you want to use.
sudo xcode-select -switch /Applications/Xcode5-DP6.app/Contents/Developer
If you have run pod install in the past, you may need to update:
pod update