Hi! Here's the finished file, everything works fine for me.
The trendTMACGLWMA.mq4 indicator code (file 1) won't work without the TMA+CG mladen NRP.ex4 file in the indicators folder.
Here's why:
iCustom function: Your code uses the iCustom(..., "TMA+CG mladen NRP", ...) function. This command literally tells the terminal: "Find a file named 'TMA+CG mladen NRP' and ask it for its value."
Lack of math: File 1 itself doesn't contain formulas for calculating the TMA channel. It relies entirely on calculations from an external file.
If the file is missing: The iCustom function will return 0 or an error. As a result, your indicator will either not draw anything at all or will show incorrect signals (since it will compare the moving average to zero).
This is simply a "shell" that draws arrows/histograms. The "brains" and calculations are in the second file. They should be in the same folder.