INDIRECT will not take the input string and evaluate it as an expression; rather, it takes an input string and tries t convert it to a range reference.
For example, if I8 contains (or has a formula that returns):
'[xxxxx xxxxxxx 062510 (5).xls]6'!$C:$L
then your formula in J8 could be:
=VLOOKUP(A8,INDIRECT(I8),10,FALSE)