Link is dead
That's an old post (made > 6 years ago) for LPCXpresso IDE v3. The current LPCXpresso FAQs (for IDE v8) are at:
https://community.nxp.com/community/lpcxpresso-ide/lpcxpresso-ide-faqs
And creating hex files is covered in:
Generating srec, binary and ihex files
Post-processing your linked application
Regards,
LPCXpresso Support