I fixed it in upstream. But doublecmd-0.6.x does not support Free Pascal 3.0. Because fpc-3.0 has some serious backward incompatible changes. I already started porting doublecmd-0.7 to Free Pascal 3.0. I plan to release it after official Free Pascal 3.0 and Lazarus 1.6 release.
Regards, Alexander Koblov