Ensure your copy of TMS FMX UI Pack 3.7.2.5 includes the /Source directory. If it doesn't, contact your distributor to upgrade to the full source license today.
Unlike some component packs that are simply ported over from Windows-centric VCL architecture, the TMS FMX UI Pack is built from the ground up for FireMonkey. TMS FMX UI Pack 3.7.2.5 Full Source Code