Undeletable Opnex Market Campaign Options

[tobean]

I have never used OpenX Market until now but in one zone I have a banner entry

"OpenX Market contract campaign ads"

with an id, probability value and priority (5/10) which cannot be edited or deleted.

In trying to get rid of it I have deleted the OpenX Market plugin and I also followed the instructions of Mentor posted here: http://forum.openx.org/index.php?showtopic=503427614

But the entry is still there.

In the database I still have 2 tables

ox_ext_market_advertiser
oa_ext_market_stats

Can I drop them without risk? Has anyone a solution?

Thank you!