Script: D:\UBBMSB\validus7.0\ubbthreads-7-0-b1\scripts\showflat.inc.php
Line#: 224
SQL Error: Table '.\validus\ubbt_posts' is marked as crashed and should be repaired
SQL Error #: 145
Query: SELECT t1.TOPIC_ID,t1.FORUM_ID,t1.TOPIC_LAST_REPLY_TIME,t1.TOPIC_IS_STICKY,t1.POST_ID FROM ubbt_TOPICS as t1, ubbt_POSTS as t2 WHERE t2.POST_ID = 21537 AND t1.TOPIC_ID = t2.TOPIC_ID

apparently a large post crashed it.

If you have shell access:
myisamchk -r ubbt_POSTS.MYI

If you don't have shell access then you'll need to do it through a SQL interface, either through the control panel or using something like phpmyadin

REPAIR TABLE ubbt_POSTS

aye I did. Haveing a wierd issue that just popped up with large posts. It creates a topic with no post id's and bombs out. lists it as a post and then says sorry cant find your post.

Crazyy works ok one instance and not the other. might be a crashed table.