"Quite Unexpectedly"

I have been running CS4 with no problems for over a month. As of a few days ago, when I lauch CS4, I get the beachball. I force a quit, relaunch and all is well. When I quit from that successful relaunch, I get a warning that Photoshop quit unexpectedly--of course, from my point of view there was nothing unexpected about it. I have run Onyx, restarted etc. I have read the report but it means nothing to me:

Process: Adobe Photoshop CS4 [161]
Path: /Applications/Adobe Photoshop CS4/Adobe Photoshop CS4.app/Contents/MacOS/Adobe Photoshop CS4
Identifier: com.adobe.Photoshop
Version: 11.0 (11.0x20080919 [20080919.r.488 2008/09/19:02:00:00 cutoff; r branch]) (11.0)
Code Type: X86 (Native)
Parent Process: launchd [92]

Date/Time: 2008-11-22 06:49:06.936 -0500
OS Version: Mac OS X 10.5.5 (9F33)
Report Version: 6

Exception Type: EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000020
Crashed Thread: 0

I have recently installed the trial version of Nik Effects--this is the only new thing I can think of. I have full backups (both Time Machine and Super Duper).

Can anyone give me a clue what I should do? Reinstall CS4? Delete Nik Effects? As of now, it works, I just have to lauch twice and put up with the erroneous quit warning but I would like to get to the bottom of this.

Get rid of Nik Effects - as you said this is the only new thing and could be messing things up.

Regretfully

your instincts were correct. I have removed Nik effects and there is no problem. Thank you (even if it wasn't the answer I wanted). Now I will write to them. Their website states it is CS4 compatible with Macs but I am wondering if they need to tweak it. I have my heart set on buying this, wish it was an "easy purchase", ha! Again, thank you for the nudge in the right direction.