I've got this too since late this afternoon. The browser refuses to start due to "low memory". As far I can see microb is the only app affected. Booting from mmc, feature upgraded two days ago.
About product says null when booted from mmc... From flash everything works so far.
Very strange.

I've tried rebooting, I've tried reinserting my SD cards, I've tried removing swap, I've tried recreating swap. Nothing will allow my browser to start up again.
I'm going to be reeeeeealy ticked if I have to reflash my N800.

Are other apps affected guys?
Or is it only the browser and "About product"...

Only browser and about product... so far.

I'm now seeing the same problem. On two separate n800's.

One of them (girlfriend's) is newly flashed to diablo (last night) and fully upgraded.
I boot mine from MMC, and when I boot from there it's coming up with the operation disabled error, but when I boot from flash it isn't.

maemo-launcher and browserd sees to be using up the most memory... I'm going to monitor for a while...

Ditto, x 2

strace browser

execve("/usr/bin/browser", ["browser"], [/* 50 vars */]) = 0
brk(0) = 0x12000
uname({sys="Linux", node="Nokia-N810-23-14", ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x4001b000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=32204, ...}) = 0
mmap2(NULL, 32204, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40024000
close(3) = 0
open("/lib/libc.so.6", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\32 4B\1\0004\0\0\0\210"..., 512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1082808, ...}) = 0
mmap2(NULL, 1118708, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x4002c000
mprotect(0x40130000, 32768, PROT_NONE) = 0
mmap2(0x40138000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x104) = 0x40138000
mmap2(0x4013b000, 8692, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x4013b000
close(3) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x4001c000
set_tls(0x4001c080, 0x4001c080, 0x40023048, 0x4001c758, 0x40) = 0
mprotect(0x40138000, 4096, PROT_READ) = 0
munmap(0x40024000, 32204) = 0
brk(0) = 0x12000
brk(0x33000) = 0x33000
access("/usr/bin/browser.launch", X_OK) = 0
getpriority(PRIO_PROCESS, 0) = 20
socket(PF_FILE, SOCK_STREAM, 0) = 3
connect(3, {sa_family=AF_FILE, path="/tmp/.maemo-launcher"...}, 110) = 0
write(3, "\1\3\7\260"..., 4) = 4
read(3, "\0\0\r`"..., 4) = 4
write(3, "\0\0^Z"..., 4) = 4
write(3, "\10\0\0\0"..., 4) = 4
write(3, "browser\0"..., 8) = 8
read(3, "\0\0\r`"..., 4) = 4
write(3, "\0\0\354\350"..., 4) = 4
write(3, "\30\0\0\0"..., 4) = 4
write(3, "/usr/bin/browser.launch\0"..., 24) = 24
read(3, "\0\0\r`"..., 4) = 4
write(3, "\0\0e\244"..., 4) = 4
write(3, "\1\0\0\0"..., 4) = 4
write(3, "\10\0\0\0"..., 4) = 4
write(3, "browser\0"..., 8) = 8
read(3, "\0\0\r`"..., 4) = 4
write(3, "\0\0\316\241"..., 4) = 4
write(3, "\0\0\0\0"..., 4) = 4
read(3, "\0\0\r`"..., 4) = 4
write(3, "\0\0\255\336"..., 4) = 4
read(3, "\0\0\r`"..., 4) = 4
read(3, "\0\0\35\35"..., 4) = 4
read(3, "L\7\0\0"..., 4) = 4
setrlimit(RLIMIT_CORE, {rlim_cur=0, rlim_max=0}) = 0
rt_sigaction(SIGHUP, {0x8adc, [], SA_RESTART|0x4000000}, NULL, 8) = 0
rt_sigaction(SIGINT, {0x8adc, [], SA_RESTART|0x4000000}, NULL, 8) = 0
rt_sigaction(SIGQUIT, {0x8adc, [], SA_RESTART|0x4000000}, NULL, 8) = 0
rt_sigaction(SIGTERM, {0x8adc, [], SA_RESTART|0x4000000}, NULL, 8) = 0
rt_sigaction(SIGUSR1, {0x8adc, [], SA_RESTART|0x4000000}, NULL, 8) = 0
rt_sigaction(SIGUSR2, {0x8adc, [], SA_RESTART|0x4000000}, NULL, 8) = 0
rt_sigaction(SIGWINCH, {0x8adc, [], SA_RESTART|0x4000000}, NULL, 8) = 0
read(3, 0xbecec580, 4) = ? ERESTARTSYS (To be restarted)
--- SIGWINCH (Window changed) @ 0 (0) ---
kill(1868, SIGWINCH) = 0
sigreturn() = ? (mask now [])
read(3, "\0\0\27\344"..., 4) = 4
read(3, "\0\1\0\0"..., 4) = 4
rt_sigaction(SIGHUP, {SIG_DFL}, NULL, 8) = 0
rt_sigaction(SIGINT, {SIG_DFL}, NULL, 8) = 0
rt_sigaction(SIGQUIT, {SIG_DFL}, NULL, 8) = 0
rt_sigaction(SIGTERM, {SIG_DFL}, NULL, 8) = 0
rt_sigaction(SIGUSR1, {SIG_DFL}, NULL, 8) = 0
rt_sigaction(SIGUSR2, {SIG_DFL}, NULL, 8) = 0
rt_sigaction(SIGWINCH, {SIG_DFL}, NULL, 8) = 0
close(3) = 0
exit_group(1) = ?

Anyone?

From Tablet number 1 when running:

maemo-summoner /usr/bin/browser.launch

/usr/bin/browser[2147]: GLIB DEBUG default - g == 0x0 should do something about not being able to connect
/usr/bin/browser[2147]: GLIB CRITICAL ** default - LOW Mem: connection to server fail: exiting
/usr/bin/browser[2147]: GLIB CRITICAL ** default - browser_download_mgr_suspend: assertion `BROWSERDOWNLOAD_MGR(self)' failed
/usr/bin/browser[2147]: GLIB CRITICAL ** default - browser_engine_sleep: assertion `self->web' failed

The other has a slightly cut-down version of the same error, with just the first two lines...

Edit: Scrap that, looks like it's usually that busy...

So basically my tablet is useless to browse the web until this is fixed or until I reflash?
Is there a bug entry for this yet?

If any others are having this problem, please speak up!

Edit: It almost looks like maemo-launcher is eating up tons of memory when looking at 'top'.

https://bugs.maemo.org/show_bug.cgi?id=3586
I added some of my info to the official bug report.