hi,
If you run that sim from your desktop you will get the cannot find 'tectriac.lib', which is what you would expect.
If you look in C:\Program Files\LTC\LTspiceIV\lib, you will see the tectriac.lib.
Open the tectriac.lib using a text editor, you will see the L6008L6 listed amongst many other Triacs, near the end of the file.
When using F2 and 'Triac_SCR' folder 'TRIAC_Teccor uses the L6008L6 as its default model.
If you want to choose one from the list in the above lib file, just replace the L6008L6 with the new type number on your asc file drawing.
So you dont have to include tectriac.lib, its part of LTS.
If you use another triac.lib, you could place it in the Libs and include as required.
E.