Doesnt help a bit. You havent shown us what modules you are using, where does pp() come from. you havent shown us where $tree or $i are assigned.

you may get a clue as to what is going on if you put these two statements before what you showed us. 

use Data::Dumper; 
print Dumper($tree);

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In reply to Re^3: HASH value error by huck
in thread HASH value error by pdahal

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