Ext3 500GB HDD mounted only as read-only

[MichaelPeppers]

As the title says, everytime I'm trying to mount this Harddisk in R/W mode it silently fails then Haiku proceeds to mount it as read-only. Syslog only says this:

KERN: [34mext2:[0m Inode::EnableFileCache(): Failed to create file cache
KERN: [34mext2:[0m AllocationBlockGroup(226,7405568)::Initialize(): Mismatch between counted free blocks (16375/32768) and what is set on the group descriptor (0)
KERN: [34mext2:[0m could not initialize block allocator, going read-only!

On every other system I use this HDD (Win XP, Linux Mint Debian) it works in R/W mode just fine (StyledEdit is not showing some characters on these lines by the way)