Does this Kernel panic look like a hardware or software issue?

Here’s the log from a kernel panic that has occured a few times over the last week or two, and it’s starting to bug me. Any ideas?

Macbook w/ OS 10.5.5 Leopard

Tue Oct 28 11:29:39 2008
Panic: Unresponsive processor
EAX: 0×00300600, EBX: 0×03dfb000, ECX: 0×31333934, EDX: 0×0816a172
CR2: 0×00108e4c, EBP: 0×00108e98, ESI: 0×2e535000, EDI: 0×00000001
EFL: 0×00000082, EIP: 0×00866da8, CS: 0×00000008, DS: 0×00100010
Backtrace (CPU 0), Frame : Return Address (4 potential args on stack)
0×108da8 : 0×1af85c (0×50ff344 0×50ff358 0×2bd88a 0×6)
0×108dc8 : 0×447f78 (0×2 0×108e18 0xc2c 0×0)
0×108e08 : 0×19f1fb (0×108e18 0×1 0xe 0×48)
0×108e98 : 0×866ea8 (0×3dfb000 0×3e37880 0×108f28 0×3dff800)
0×108eb8 : 0×422c3b (0×3dfb000 0×3e37880 0×3cc5f80 0×3d21000)
0×108ef8 : 0×437e99 (0×3e37880 0×0 0×3de1380 0×0)
0×108f28 : 0xa22521 (0×3dfeb00 0×0 0×3dfeb00 0×0)
0×108f58 : 0×888777 (0×3d98f00 0×0 0×3d8eb00 0×53)
0×108f78 : 0×881c41 (0×3d22400 0×0 0×3d8eb00 0×53)
0×108f98 : 0×447f9f (0×3d8e680 0×0 0×3d8e600 0×53)
Backtrace continues…
Kernel loadable modules in backtrace (with dependencies):
com.apple.driver.AppleFWOHCI(3.4.4)@0×860000—>0×87ffff
dependency: com.apple.iokit.IOFireWireFamily(3.4.4)@0×821000
dependency: com.apple.iokit.IOPCIFamily(2.4.1)@0×5c1000
com.apple.driver.AppleAPIC(1.2.0)@0xa21000—>0xa23fff
com.apple.driver.AppleACPIPlatform(1.2.1)@0×880000—>0×8bcfff
dependency: com.apple.iokit.IOPCIFamily(2.4.1)@0×5c1000
dependency: com.apple.iokit.IOACPIFamily(1.2.0)@0×629000
Kernel loadable modules in backtrace (with dependencies):
com.apple.driver.AppleFWOHCI(3.4.4)@0×860000—>0×87ffff
dependency: com.apple.iokit.IOFireWireFamily(3.4.4)@0×821000
dependency: com.apple.iokit.IOPCIFamily(2.4.1)@0×5c1000

BSD process name corresponding to current thread: Adobe Photoshop

Mac OS version:
9F33

Kernel version:
Darwin Kernel Version 9.5.0: Wed Sep 3 11:29:43 PDT 2008; root:xnu-1228.7.58~1/RELEASE_I386
System model name: MacBook1,1 (Mac-F4208CC8)
panic(cpu 1 caller 0×00193077): “pmap_flush_tlbs() timeout: ” “cpu(s) failing to respond to interrupts, pmap=0×536500 cpus_to_respond=0×1”@/SourceCache/xnu/xnu-1228.7.58/osfmk/i386/pmap.c:4580
Backtrace (CPU 1), Frame : Return Address (4 potential args on stack)
0×342ab4b8 : 0×12b0fa (0×459234 0×342ab4ec 0×133243 0×0)
0×342ab508 : 0×193077 (0×45f3a4 0×536500 0×1 0×0)
0×342ab578 : 0×19420b (0×536500 0×2cf90000 0×0 0×122f7)
0×342ab618 : 0×17406f (0×122f7 0×0 0×1 0×6565070)
0×342ab6b8 : 0×169e3a (0×6c83348 0×0 0×0 0×1000)
0×342ab7d8 : 0×16a437 (0×2cf91000 0×0 0×0 0×0)
0×342ab818 : 0×1824c7 (0×16b7d20 0×2cf90000 0×0 0×2cf91000)
0×342ab878 : 0×42d220 (0×16b7d20 0×2cf90000 0×0 0×1000)
0×342ab8d8 : 0×42d284 (0×91d5900 0×16b7f78 0×69f3180 0×0)
0×342ab8f8 : 0×42d375 (0×69f3180 0×50 0×1 0×0)
0×342ab918 : 0×42d34c (0×69f3180 0×0 0×2 0×0)
0×342ab938 : 0×3eb7f9 (0×69f3180 0×0 0×4 0×1658)
0×342ab958 : 0xc3e990 (0×69f3180 0×85f3d00 0×342ab9a8 0×420)
0×342ab9a8 : 0xc407f9 (0×49dc000 0×85f3d00 0×2519021 0×594)
0×342abb98 : 0xc2a009 (0×49dc000 0×342abc60 0×0 0×0)
0×342abc88 : 0×4397e0 (0×49dc000 0×1 0×342abcdc 0×342abcd8)
Backtrace continues…
Kernel loadable modules in backtrace (with dependencies):
com.apple.driver.AppleIntelGMA950(5.3.0)@0xc21000—>0xc57fff
dependency: com.apple.iokit.IONDRVSupport(1.5.2)@0×6b2000
dependency: com.apple.iokit.IOPCIFamily(2.4.1)@0×5c1000
dependency: com.apple.iokit.IOGraphicsFamily(1.5.2)@0×639000

BSD process name corresponding to current thread: WindowServer