Note that "text file" may be a little bit misleading here. It does not mean a file containing ASCII text, like e.g. a README document. "text" in this context means executable machine code, i.e. a (binary) program or a library used by a program. Look what file can't be unlinked, and search it in the list of running programs (top / ps). Terminate that program after you have made sure that doing so won't do any harm to the system.

Alexander