Which version of the operating system are you using?
What model of camcorder is your video coming from and what format is it?
When you start your Premiere Elements project, which project settings are you selecting? If you're selecting the correct project settings, there will be no red lines above the clips when you add them to your timeline. Is that what is happening in your projects?
Do you render your timelines whenever you see red lines above the clips?
First, we highly recommend against using two such different formats in the same project. It almost always leads to problems.
Second, your project settings are incorrect for BOTH formats.
I could find no specs on the SDR SW2, so I don't know what format, resolution and codec it uses for its video. MOD files are usually standard definition 720x480 (720x576 PAL), but without knowing, I can't advise you on the project settings.
The HDC SD60 is an AVCHD camcorder. To edit this video, your project should be set up for AVCHD 1920x1080.
In any event, these two video formats should NOT be used in the same project together. And, as I explain in my books as well ias well as in my Basic Training tutorials, matching your project settings to your source video is VITAL to a successful video editing experience.
Even if you are using different clips on different project settings which is although not advisable, it should NOT crash.
Also, I couldn't figure out what would be causing the issue, but I would suggest you to have enough empty space on your HardDisk.
And, there was an update for Adobe Premiere Elements 9. Maybe, that will help.
The update can be found here
Hope it helps,
I searched for updates but elements says it's already the latest version. when i started element at one mac I got an error. I saved the report and this is just a small part of it (the latest thread is 035)
getting a little bit hopeless over here :-(
Process: Adobe Premiere Elements 
Path: /Applications/Adobe Premiere Elements 9/Adobe Premiere Elements.app/Contents/MacOS/Adobe Premiere Elements
Identifier: com.adobe.Adobe Premiere Elements.framework
Version: N224.08092010.240488 (9.0)
Code Type: X86 (Native)
Parent Process: launchd 
Date/Time: 2012-03-06 10:24:27.849 +0100
OS Version: Mac OS X 10.6.8 (10K549)
Report Version: 6
Interval Since Last Report: 1447115 sec
Crashes Since Last Report: 23
Per-App Interval Since Last Report: 80154 sec
Per-App Crashes Since Last Report: 5
Anonymous UUID: 9F46D124-2F72-4F85-BE42-C4E8565DD702
Exception Type: EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000002, 0x0000000000000000
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Thread 0 Crashed: Dispatch queue: com.apple.main-thread
0 com.adobe.dvacore.framework 0x0018cebc dvacore::utility::ThreadSafeMessageDialog(char const*) + 380
1 com.adobe.dvacore.framework 0x0009baab dvacore::debug::BreakAfterContractDialog(char const*, char const*, int) + 251
2 ...ore.Frameworks.AudioSupport 0x038be022 ML::CoreAudioHost::LoadCoreAudioDriver(std::basic_string<unsigned short, std::char_traits<unsigned short>, dvacore::utility::SmallBlockAllocator::STLAllocator<unsigned short> > const&) + 642