Try with that :

#-replace DB name
# TNSNAMES.ORA Network Configuration File: C:\oracle\ora90\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.

SPOORNET =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = ROBCOMPUTER)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = SPOORNET)
)
)

a =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = LOGICSTOO)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = a)
)
)

TEST =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = LOGICSTOO)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = TEST)
)
)

b =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = LOGICSTOO)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = b)
)
)


There is a carriage return after the last )

(I also changed the names with the ###, not to good names are they ?)