Double Commander

As far as I use Double Commander on Mac OS X Lion, I always get an error message when I open a zip file:

"
Executable not found: "/Applications/Double Commander.app/Contents/MacOS/7za"
"

What is the cause of this error? There is no such file in the file system. (version 0.5.5 alpha build 4888M, but the stable version is also buggy)

I very like the Double Commander on Win, but the Mac OS X version is very buggy. There is no normal Total Commander alternative on Mac OS X, except Double Commander.

Please fix this zip error. Thank you in advance.

What should I do?

--------------- 07-08-2012, 12:11:08 ---------------
| DC v0.5.5 alpha Rev. 4937M -- i386-Darwin-carbon
| Mac OS X 10.7.4
Unhandled exception: EProcess: Executable not found: "/Applications/Double Commander.app/Contents/MacOS/7za"
Stack trace:
$0012C94F
$0058F71D
$00590BF5
$0032ACBD
$004B1709
$000B99F7