I've explained this at length in this post:
http://www.cdrinfo.com/forum/tm.asp?m=7 ... ter𓖑
PI error is a inner parity error in the reading process of a dvd disc. A reading process should have no more than 280 of inner parity errors in any eight consecutive blocks on the disc.
PI failure is an uncorrectable PI error that flags the row of a block to be uncorrectable at inner parity stage of error correction. Outer parity error correction will then try to fix these uncorrectable PI errors.
BD-R is the equivalent of DVD-R for the next generation of writable dvd discs called Blu-Ray.
DVD+R9 is the dual layer version of the recordable DVD+R disc.
You can find more about these in a dvd glossary of terms: