Class 'FileLog' not found (line 63 of /var/www/pw/wire/core/WireLog.php)

[valan]

Recently I've discovered strange issue: wire()->log->error('smth') stopped working with error message being emailed to admin (see topic).

But FileLog.class.php was in /wire/core !

After several hours of useless attempts to fix issue I've occasionally entered file, added insignificant space and saved file - after that issue disappeared! However, after several hours it appeared again....

Did anybody met this kind of issue? I guess smth could be wrong either at OS (debian 7) or PHP (5.5) level but I don't know were to start digging... please advice. Thanks!

P.S. I'm still running PW 2.3.11.