I've repeated the process using PS 5.5.16-55 (binary package for Debian Squeeze) and XB 2.0.3. I've loaded 1 warehouse. This is the crash I get when I try to select the table order_line (other tables seems to work):

121126 13:44:31 - mysqld got signal 6 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help diagnose
the problem, but since we have already crashed, something is definitely wrong
and this may fail.

key_buffer_size=16777216
read_buffer_size=131072
max_used_connections=1
max_threads=151
thread_count=1
connection_count=1
It is possible that mysqld could use up to 
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 346766 K
bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x32428b0
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
stack_bottom = 0x7fb50d590e88 thread_stack 0x30000
/usr/sbin/mysqld(my_print_stacktrace+0x39)[0x7bd8c9]
/usr/sbin/mysqld(handle_segfault+0x464)[0x519884]
/lib/libpthread.so.0(+0xeff0)[0x7fb50d1a3ff0]
/lib/libc.so.6(gsignal+0x35)[0x7fb50c39f1b5]
/lib/libc.so.6(abort+0x180)[0x7fb50c3a1fc0]
/usr/sbin/mysqld[0x88d525]
/usr/sbin/mysqld[0x83d187]
/usr/sbin/mysqld[0x83dbc5]
/usr/sbin/mysqld[0x81579d]
/usr/sbin/mysqld[0x5b170d]
/usr/sbin/mysqld(_Z10sub_selectP4JOINP13st_join_tableb+0x79)[0x5ba529]
/usr/sbin/mysqld[0x5bb4d2]
/usr/sbin/mysqld(_ZN4JOIN4execEv+0xc40)[0x5d0bb0]
/usr/sbin/mysqld(_Z12mysql_selectP3THDPPP4ItemP10TABLE_LISTjR4ListIS1_ES2_jP8st_orderSB_S2_SB_yP13select_resultP18st_select_lex_unitP13st_select_lex+0x12c)[0x5cc6ac]
/usr/sbin/mysqld(_Z13handle_selectP3THDP3LEXP13select_resultm+0x1cd)[0x5d23ad]
/usr/sbin/mysqld[0x58fb22]
/usr/sbin/mysqld(_Z21mysql_execute_commandP3THD+0x1236)[0x5935b6]
/usr/sbin/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x313)[0x596df3]
/usr/sbin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x15a2)[0x598442]
/usr/sbin/mysqld(_Z24do_handle_one_connectionP3THD+0xdf)[0x631f7f]
/usr/sbin/mysqld(handle_one_connection+0x51)[0x6320b1]
/lib/libpthread.so.0(+0x68ca)[0x7fb50d19b8ca]
/lib/libc.so.6(clone+0x6d)[0x7fb50c43cb6d]

Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (0x32d4740): select count(*) from order_line
Connection ID (thread ID): 1
Status: NOT_KILLED

SHOW TABLES also (sometimes) crashes the server:

121126 13:47:30 - mysqld got signal 11 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help diagnose
the problem, but since we have already crashed, something is definitely wrong
and this may fail.

key_buffer_size=16777216
read_buffer_size=131072
max_used_connections=1
max_threads=151
thread_count=1
connection_count=1
It is possible that mysqld could use up to 
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 346766 K
bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x2bbf8b0
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
stack_bottom = 0x7f6a4cf25e88 thread_stack 0x30000
/usr/sbin/mysqld(my_print_stacktrace+0x39)[0x7bd8c9]
/usr/sbin/mysqld(handle_segfault+0x464)[0x519884]
/lib/libpthread.so.0(+0xeff0)[0x7f6a4cb39ff0]
/usr/sbin/mysqld[0x9338d6]
/usr/sbin/mysqld[0x88aa3f]
/usr/sbin/mysqld[0x8bc56f]
/usr/sbin/mysqld[0x8bf618]
/usr/sbin/mysqld[0x8197e8]
/usr/sbin/mysqld(_ZN7handler7ha_openEP5TABLEPKcii+0x3e)[0x690e8e]
/usr/sbin/mysqld(_Z21open_table_from_shareP3THDP11TABLE_SHAREPKcjjjP5TABLEb+0x58c)[0x60d9bc]
/usr/sbin/mysqld(_Z10open_tableP3THDP10TABLE_LISTP11st_mem_rootP18Open_table_context+0xc53)[0x55c2c3]
/usr/sbin/mysqld(_Z11open_tablesP3THDPP10TABLE_LISTPjjP19Prelocking_strategy+0x4f6)[0x55d046]
/usr/sbin/mysqld(_Z30open_normal_and_derived_tablesP3THDP10TABLE_LISTj+0x48)[0x55d988]
/usr/sbin/mysqld(_Z18mysqld_list_fieldsP3THDP10TABLE_LISTPKc+0x25)[0x5e2185]
/usr/sbin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0xa9d)[0x59793d]
/usr/sbin/mysqld(_Z24do_handle_one_connectionP3THD+0xdf)[0x631f7f]
/usr/sbin/mysqld(handle_one_connection+0x51)[0x6320b1]
/lib/libpthread.so.0(+0x68ca)[0x7f6a4cb318ca]
/lib/libc.so.6(clone+0x6d)[0x7f6a4bdd2b6d]

Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (0x2c51748): 
Connection ID (thread ID): 1
Status: NOT_KILLED