PS CS4: Actions Won't Work And PS Crashes

I just bought PS Cs4 online and I'm having many issues with it. At first, everything is fine but when i try to use some actions, they don't work. I'm using a action that i made myself and when i play it, it tells me that the command "merge visible" is not currently available. The same happens with other actions about different commands, even with some of the actions that already comes with PS like the water reflection one. After that, alot of my short-cuts stop working, like the ones for brush, crop, clone stamp...pretty much all the tools short-cuts. Then, when I try to close PS, it just doesnt. I have to force quit it. And if I just keep working on it, PS will crash and take me to a blue screen. I'm using Snow Leopard with the lastest upgrade from Apple. I dont know if this will help but I went to Mac OS console and I'm getting this:

10/13/09 12:17:43 PM [0x0-0x1c01c].com.adobe.Photoshop[187] Adobe Photoshop CS4(187,0xa0b8e5c0) malloc: *** error for object 0x5d00820: Non-aligned pointer being freed (2)
10/13/09 12:17:43 PM [0x0-0x1c01c].com.adobe.Photoshop[187] *** set a breakpoint in malloc_error_break to debug
10/13/09 12:17:45 PM [0x0-0x1c01c].com.adobe.Photoshop[187] Adobe Photoshop CS4(187,0xa0b8e5c0) malloc: *** error for object 0x5d17900: Non-aligned pointer being freed (2)
10/13/09 12:17:45 PM [0x0-0x1c01c].com.adobe.Photoshop[187] *** set a breakpoint in malloc_error_break to debug
10/13/09 12:17:45 PM [0x0-0x1c01c].com.adobe.Photoshop[187] Adobe Photoshop CS4(187,0xa0b8e5c0) malloc: *** error for object 0x5d17dd0: Non-aligned pointer being freed (2)
10/13/09 12:17:45 PM [0x0-0x1c01c].com.adobe.Photoshop[187] *** set a breakpoint in malloc_error_break to debug
10/13/09 12:17:45 PM [0x0-0x1c01c].com.adobe.Photoshop[187] Adobe Photoshop CS4(187,0xa0b8e5c0) malloc: *** error for object 0x5d17e50: Non-aligned pointer being freed (2)
10/13/09 12:17:45 PM [0x0-0x1c01c].com.adobe.Photoshop[187] *** set a breakpoint in malloc_error_break to debug
10/13/09 12:18:05 PM [0x0-0x1c01c].com.adobe.Photoshop[187] file://localhost/Applications/Adobe P
10/13/09 12:18:09 PM [0x0-0x1c01c].com.adobe.Photoshop[187] file://localhost/Applications/Adobe P
10/13/09 12:20:13 PM [0x0-0x1c01c].com.adobe.Photoshop[187] Adobe Photoshop CS4(187,0xa0b8e5c0) malloc: *** mmap(size=17002496) failed (error code=12)
10/13/09 12:20:13 PM [0x0-0x1c01c].com.adobe.Photoshop[187] *** error: can't allocate region
10/13/09 12:20:13 PM [0x0-0x1c01c].com.adobe.Photoshop[187] *** set a breakpoint in malloc_error_break to debug
10/13/09 12:20:13 PM [0x0-0x1c01c].com.adobe.Photoshop[187] Adobe Photoshop CS4(187,0xa0b8e5c0) malloc: *** mmap(size=17002496) failed (error code=12)
10/13/09 12:20:13 PM [0x0-0x1c01c].com.adobe.Photoshop[187] *** error: can't allocate region