[support] update script problems

[Armin Medosch]

hi,

whenever i try to run the database update script, for instance after
installing a new version of a module, I get

HTTP error 501 occured. update.php?op=do_update


If I then click on update summary i get

The update process was aborted prematurely while running update #5000 in
blogapi.module. All other errors have been logged. You may need to check
the watchdog database table manually.

Maybe not related: 

for lack of time I have not done complete upgrades since 5.7 but only
always applied the security patches. now users using mozilla on macs
report severe problems such as the submit buttons missing when trying to
contribute something

is this a known problem? has this anything to do with not having done
upgrades, only patching? 

best regards and thanks for any help
armin