I don't know much more than Jim on this bankruptcy, but I believe these corporate shells ran out of the the money they came with, which Berkshire was able to invest in securities, while still having significant liabilities to pay and unresolved cases still out there. Rather than let the next few judgements "win" everything that was left, they felt it was more equitable to divide what is left more evenly among everybody in line. The timing of this filing was based on a March 6th jury verdict awarding $29 million.

I don't know why Berkshire, specifically Ringwalt & Liesche Co, bought the corporate shells but they probably knew at the time the worst case scenario was for the shells to run out of funds and file BK.

Free Bloomberg article with some details here:
bnnbloomberg.ca - Talc supplier to cosmetics firms files bankruptcy after lawsuits