Earlier quoted context omitted.
Code from the open-source nprof project made up a good chunk of dotTrace (confirmed via decompilation at the time).
Which licence did you distribute the code with? Surely there's solid grounds for a legal case if the licence didn't permit commercial use?
EDIT: it was clearer than I thought - v0.4 [1] has an explicit GPL 2.0 COPYING.txt in the root.
[1] https://sourceforge.net/projects/nprof/files/OldFiles/nprof-...