IIR 2.8.7 dblist Connectivity Error - Please help.

@MDMDEV

dblist> database 'odb:99:ISSUSER/@MDMDEV' open failed -91009009dblist> ErrorLog: [114161915   1] dblist  > It is now 20131114161915
dblist> ErrorLog: [114161915   1] dblist.c     1660 rc  12   91009009*100
dblist> ErrorLog: [114161915   1] dbldr.c      1088 rc   9  107091009*1000
dblist> ErrorLog: [114161915   1] dbops.c      1759 rc   9    1070910*100
dblist> ErrorLog: [114161915   1] ssaodbc.c    4164 rc  10      10709*100
dblist> ErrorLog: [114161915   1] ssadb8_db_opn failed
dblist> ErrorLog: [114161915   1] ssaodbc.c    3837 rc   9        107*100
dblist> ErrorLog: [114161915   1] db_connect_user: Cannot connect to service 'MDMDEV' with uid 'ISSUSER'
dblist> ErrorLog: [114161915   1] ssaodbc.c    1277 rc   7          1*100
dblist> ErrorLog: [114161915   1] ssa_odbc_connect: cannot connect to Data Source
dblist> ErrorLog: [114161915   1] ssaoci.c     2640 rc   2
dblist> ErrorLog: [114161915   1] SQLConnect: OCIInitialize failed -1
Maximum connections per module: 1024
Linked databases: sdb: odb:


Not able to resolve the above error please help me on this.