FrequencyTimer2.h: so such file or directory
That stuff is case sensitive, use always exactly the same string, for your files, directories and in the sketch.
That, in my personal opinion, is an awful font. I can't tell whether the characters are capitals or not. In FREQUENCYtiMER2, which, if any, are actually capitals?
That isn't the correct place to put non-standard libraries. They should go in your sketchbook library folder.
just the F and the T, thats the only letters in capitals
Quotejust the F and the T, thats the only letters in capitalsAre you sure? If you look at FLEXItiMER and FIRMATA, the F is taller than the other characters, in FREQUENCYtiMER2, the F is the same height as the others. The f in fiRMWARE and SOftWARESERIAL appears as lower case. How do you work with that font?Can you open a command window and check that way?
If the F and T are capital, the directory is not the same as the containing files. The name of the directory (including case) is read from the include statement. If you have "frequencytimer2.h" there, then the library has to be in the path "libraries/frequencytimer2/frequencytimer2.h" and "libraries/frequencytimer2/freqencytimer2.cpp". Have you checked that? BTW: me too, I would never work with such a horrible font. Might be ok for a flyer but not as a desktop font.