Recurring Kernel Panic Crashes

Question

hi folks. okay, i am new here and not too super-tech savvy, but am having an annoying problem with my new G5.
i bought a refurbed Dual 2.5 G5 from the apple store a month ago. (not the dualcore, and not the line before it, but the product line before that, when 2.5Ghz was the top model.) ever since i got it i have been having constant Kernel Panics (the screen goes dark and says "You need to restart your Computer")
i have not yet added ANY external devices. but the weird thing is: it is ONLY happening when i am connected to the internet and browsing, regardless of what app i am using (Safair, Navi, Firefox, IExplor.) it has not happened any other times.
now, so far i have repaired disk permissions, but this hasnt helped. i dont know what to do. i am wondering if it has something to do with the modem connection, as i am using the built in 56k V.92, so i worry that this may be a cause.
I am in a weird position because, since it is a refurb, i wonder if maybe whatever it is that had it returned for refurbing may still be haunting the system. At this point, i dont feel i should have to go out and spend more money to buy TechTool or something like that simply to troubleshoot the problem. i am hoping to get some advice here before i contact customer service.
Here are my specs.
Dual 2.5Ghz PowerPC G5
512 MB DDR SDRAM
OSX 10.4
no external devices added yet, and i am not doing anything that would be excessing the current amount of RAM (unless the RAM itself is corrupted)
here is a quick copy of the most recent Panic Log:
Unresolved kernel trap(cpu 0): 0x300 - Data access DAR=0x000000001D932005 PC=0x000000002373E890
Latest crash info for cpu 0:
Exception state (sv=0x1D03CA00)
PC=0x2373E890; MSR=0x00009030; DAR=0x1D932005; DSISR=0x40000000; LR=0x2373E88C; R1=0x0CFB39A0; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x002918C4 0x2373E1A8 0x0011CCF8 0x00154A1C 0x00141C94 0x0028E23C
0x00293444 0x00293618 0x002A8174 0x000ABA30 0x443D2232
backtrace terminated - frame not mapped or invalid: 0xBFFFFAD0
Kernel loadable modules in backtrace (with dependencies):
com.apple.nke.ppp(1.4)@0x2373a000
Proceeding back via exception chain:
Exception state (sv=0x1D03CA00)
previously dumped as "Latest" state. skipping...
Exception state (sv=0x2348EA00)
PC=0x9001FD00; MSR=0x0000F030; DAR=0x0046A000; DSISR=0x42000000; LR=0x00002EC4; R1=0xBFFFFAD0; XCP=0x00000030 (0xC00 - System call)
Kernel version:
Darwin Kernel Version 8.0.0: Sat Mar 26 14:15:22 PST 2005; root:xnu-792.obj~1/RELEASE_PPC
panic(cpu 0 caller 0xFFFF0003): 0x300 - Data access
Latest stack backtrace for cpu 0:
Backtrace:
0x00095564 0x00095A7C 0x00026838 0x000A8184 0x000AB880
Proceeding back via exception chain:
Exception state (sv=0x1D03CA00)
PC=0x2373E890; MSR=0x00009030; DAR=0x1D932005; DSISR=0x40000000; LR=0x2373E88C; R1=0x0CFB39A0; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x002918C4 0x2373E1A8 0x0011CCF8 0x00154A1C 0x00141C94 0x0028E23C
0x00293444 0x00293618 0x002A8174 0x000ABA30 0x443D2232
backtrace terminated - frame not mapped or invalid: 0xBFFFFAD0
Kernel loadable modules in backtrace (with dependencies):
com.apple.nke.ppp(1.4)@0x2373a000
Exception state (sv=0x2348EA00)
PC=0x9001FD00; MSR=0x0000F030; DAR=0x0046A000; DSISR=0x42000000; LR=0x00002EC4; R1=0xBFFFFAD0; XCP=0x00000030 (0xC00 - System call)
Kernel version:
Darwin Kernel Version 8.0.0: Sat Mar 26 14:15:22 PST 2005; root:xnu-792.obj~1/RELEASE_PPC
i apologize if i am overdoing it here. but i was just hoping someone out there might have a good eye for whats going on here, because i really dont want to have to send this thing back already. im a bit parnoid.
anyhow, thanks in advance.
-mplaster
Dual 2.5 PowerPC G5   Mac OS X (10.4)  

Answer 1

Welcome to Apple Discussions!
The fact that PPP is mentioned in the log suggests that either the software for connecting to the internet has some serious corruption, or there may be a problem with the modem itself. I would backup your data, and then see if the kernel panics have resulted in directory damage:
http://docs.info.apple.com/article.html?artnum=106214
If the disk appears to be OK, and you aren't using any download optimizing software, then I would definitely have the modem looked at.
If there are errors which Disk Utility can't repair through Repair Disk, then I would get Alsoft Disk Warrior 3.0.3 to attempt to repair the directory.
If your hard disk is especially full, directory corruption can happen easily.
But it can also happen for numerous other reasons, which is why I recommend backing up before attempting the directory repair.