Yep, FindBin doesn't seem to be the problem. Don't know what to say there. You can still use IMCC though.
Neither the assembler nor IMCC have anything to do with the parrot interpretter (which is actually a virtual machine). However, both the assembler and IMCC have the ability to assemble parrot assembly into parrot bytecode. Traditionally, this has been the job of the assembler, but IMCC, the optimizer, has gotten advanced enough so that it can also assemble, and is actually better at it. Give it a try! It shouldn't break like the assembler did; it is written in pure C.