ERROR 1100 (HY000) at line 11084: Table 'search_index' was not locked with LOCK TABLES
My initial guess would be that when the mysqldump file was being created, the option single-transaction was not used.

According to MySQL Documentation on single-transaction


  The --single-transaction option and the --lock-tables option are mutually exclusive because LOCK TABLES causes any pending transactions to be committed implicitly. 


The fact that you embedded UNLOCK TABLES; into the dump manually shows that neither option was called when the mysqldump was first created. Thus, upon reload, this error reared its ugly head.