problems building mozldap-6.0.3 on White Box Enterprise Linux release 3.0 with kernel version 2.4.21-27.EL

I'm trying to build mozldap-6.0.3 on White Box Enterprise Linux release 3.0 
with kernel version 2.4.21-27.EL and I'm getting the following errors, does 
anyone know what I'm doing wrong

    make[3]: Leaving directory 
`/local/src/ldap/mozldap-6.0.3/mozilla/directory/c-sdk/ldap/libraries/libldap'
cd libprldap; make BUILD_DEBUG=full export
make[3]: Entering directory 
`/local/src/ldap/mozldap-6.0.3/mozilla/directory/c-sdk/ldap/libraries/libprldap'
gcc -o 
dappr-dns.o -c     -pipe -ansi -Wall -pthread -g -fno-inline -fPIC  -DDEBUG_root 
  -DDEBUG=1 -DXP_UNIX=1 -D_POSIX_SOURCE=1 -D_BSD_SOURCE=1 -D_SVID_SOURCE=1 -D_LARGEFILE64_SOURCE=1 
 -DHAVE_FCNTL_FILE_LOCKING=1 -DLINUX=1 -Dlinux=1 -DHAVE_LCHOWN=1 -DHAVE_STRERROR=1 
 -D_REENTRANT=1  -DFORCE_PR_LOG -D_PR_PTHREADS -UHAVE_CVAR_BUILT_ON_SEM -DUSE_WAITPID 
 -DNEEDPROTOS -DLDAP_DEBUG  -DNET_SSL  -DNO_LIBLCACHE -DLDAP_REFERRALS     -DNS_DOMESTIC 
  -DLINUX2_0 -DLINUX1_2 -DLINUX2_1 -I../../../../../dist/public/ldap -I../../../ldap/include 
 -I../../../../../dist/./include   ldappr-dns.c
In file included from ldappr-dns.c:44:
ldappr-int.h:45:18: nspr.h: No such file or directory
In file included from ldappr-int.h:46,
                 from ldappr-dns.c:44:
../../../../../dist/public/ldap/ldappr.h:41:18: nspr.h: No such file or 
directory
In file included from ldappr-int.h:46,
                 from ldappr-dns.c:44:
../../../../../dist/public/ldap/ldappr.h:203: syntax error before 
"PRFileDesc"
../../../../../dist/public/ldap/ldappr.h:203: warning: no semicolon at end 
of struct or union
../../../../../dist/public/ldap/ldappr.h:205: syntax error before '}' token
../../../../../dist/public/ldap/ldappr.h:205: warning: type defaults to 
`int' in declaration of `PRLDAPSocketInfo'
../../../../../dist/public/ldap/ldappr.h:205: warning: data definition has 
no type or storage class
../../../../../dist/public/ldap/ldappr.h:221: syntax error before 
"PRLDAPSocketInfo"
../../../../../dist/public/ldap/ldappr.h:233: syntax error before 
"PRLDAPSocketInfo"
../../../../../dist/public/ldap/ldappr.h:244: syntax error before 
"PRLDAPSocketInfo"
../../../../../dist/public/ldap/ldappr.h:255: syntax error before 
"PRLDAPSocketInfo"
../../../../../dist/public/ldap/ldappr.h:260: syntax error before 
"prldap_is_installed"
../../../../../dist/public/ldap/ldappr.h:260: warning: type defaults to 
`int' in declaration of `prldap_is_installed'
../../../../../dist/public/ldap/ldappr.h:260: warning: data definition has 
no type or storage class
In file included from ldappr-dns.c:44:
ldappr-int.h:89: syntax error before "PRPollDesc"
ldappr-int.h:89: warning: no semicolon at end of struct or union
ldappr-int.h:93: syntax error before '}' token
ldappr-int.h:93: warning: type defaults to `int' in declaration of 
`PRLDAPIOSessionArg'
ldappr-int.h:93: warning: data definition has no type or storage class
ldappr-int.h:97: syntax error before "PRFileDesc"
ldappr-int.h:97: warning: no semicolon at end of struct or union
ldappr-int.h:100: syntax error before '}' token
ldappr-int.h:100: warning: type defaults to `int' in declaration of 
`PRLDAPIOSocketArg'
ldappr-int.h:100: warning: data definition has no type or storage class
ldappr-int.h:111: syntax error before "PRLDAPIOSessionArg"
ldappr-int.h:112: syntax error before '*' token
ldappr-int.h:114: syntax error before '*' token
ldappr-int.h:116: syntax error before "PRLDAPIOSocketArg"
ldappr-int.h:117: syntax error before '*' token
ldappr-int.h:117: syntax error before '*' token
ldappr-int.h:117: warning: type defaults to `int' in declaration of 
`prldap_socket_arg_alloc'
ldappr-int.h:117: warning: data definition has no type or storage class
ldappr-dns.c:55: syntax error before "PRHostEnt"
ldappr-dns.c: In function `prldap_install_dns_functions':
ldappr-dns.c:70: `PR_NETDB_BUF_SIZE' undeclared (first use in this function)