In my code I use use YAML qw{LoadFile}, and it works fine on both Windows and *nix. YAML file example:

---                                                      
version: 0.11
greek:
 - greek_plain
 - greek_italic
csr:                                                      
 FontStyle:                                               
  Italic: italic
 Position:
  Subscript: sub
  Superscript: sup
gs:
 - EPS
 - PDF
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Can you try running perl debugger on your code and using s command after LoadFile call shows up to trace code inside LoadFile?