Flan's Flying Mod doesn't require TMT anymore. Only versions before 1.4.6 require TMT. If you got this message in 1.4.6 or higher, then you have one of the following problems:

• You use a model package which requires an other package to run, e.g. a part package. You have to install these package as well. (Manus Packages require the Minecraft-SMP Part Package)
• You use a model package with a older/newer version of Flans Mod. The packages need a specific version of the mod (see Point 5d).
• You use a model package which was compiled with a new/older version of forge
• You use a model package designed for 1.2.5. Delete this package.
• You use a model package which is not proper build

Note: This Error Message was removed in 1.6.2 and replaced by a more specific message.