The latest crash was caused by Stainless Client - that may be why flash won't install. I know nothing about Stainles, but, the linked page says "Although Stainless cannot make up for the dismal performance of not being able to have the latest Flash player on PowerPC" so that makes me consider that it might interfere with flash. The second to the last crash and others before that were caused by Core Audio.
Irrelevant reports of Damaged SUID files (you don't list them) are a "known issue" with specific machines and OS's.
I'm a volunteer so I didn't look beyond the first two incidents… maybe someone else here will, sometimes fixing one or two things solves or uncovers other issues.
You know your Graphics Card is suspect or damaged (using second VGA? port). That's one piece of hardware you could replace if you have a known good card to try. I don't know with a machine this age if I'd go buy a new card unless it was less than $50.00 (how much money do you want to put into this dinosaur?)
Try booting from the original install, and repair disks.' 'Run Apple Hardware Test. Come back with results and please USE THE COMMENT LINK to reply to this answer.''
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