On a side note I'll mention that I copied the texis binary to another machine with an identical Redhat install/version just to see if I could get it to run and ended up getting the same error that is indicated by the ldd output.
Here is the output of those two commands (actually I'd been running ldd to get the library deps initially):
# ldd texis
./texis: /lib/libcrypt.so.1: version `GLIBC_2.0' not found (required by ./texis)
./texis: /lib/libm.so.6: version `GLIBC_2.1' not found (required by ./texis)
./texis: /lib/libm.so.6: version `GLIBC_2.0' not found (required by ./texis)
./texis: /lib/libc.so.6: version `GLIBC_2.1' not found (required by ./texis)
./texis: /lib/libc.so.6: version `GLIBC_2.0' not found (required by ./texis)
libm.so.6 => /lib/libm.so.6 (0x40017000)
libcrypt.so.1 => /lib/libcrypt.so.1 (0x40034000)
libc.so.6 => /lib/libc.so.6 (0x40061000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)
# strace /usr/local/apache/docroot2/cgi-bin/texis
execve("/usr/local/apache/docroot2/cgi-bin/texis", ["/usr/local/apache/docroot2/cgi-bin/texis"], [/* 19 vars */]) = 0
brk(0) = 0x84ce85c
open("/etc/ld.so.preload", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=14394, ...}) = 0
mmap(0, 14394, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40013000
close(3) = 0
open("/lib/libm.so.6", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0755, st_size=540120, ...}) = 0
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\320=\0"..., 4096) = 4096
mmap(0, 114648, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x40017000
mprotect(0x40032000, 4056, PROT_NONE) = 0
mmap(0x40032000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0x1a000) = 0x40032000
close(3) = 0
open("/lib/libcrypt.so.1", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0755, st_size=64595, ...}) = 0
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\20\f\0"..., 4096) = 4096
mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40033000
mmap(0, 183036, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x40034000
[root@gorgo /root]# strace /usr/local/apache/docroot2/cgi-bin/texis
execve("/usr/local/apache/docroot2/cgi-bin/texis", ["/usr/local/apache/docroot2/cgi-bin/texis"], [/* 19 vars */]) = 0
brk(0) = 0x84ce85c
open("/etc/ld.so.preload", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=14394, ...}) = 0
mmap(0, 14394, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40013000
close(3) = 0
open("/lib/libm.so.6", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0755, st_size=540120, ...}) = 0
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\320=\0"..., 4096) = 4096
mmap(0, 114648, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x40017000
mprotect(0x40032000, 4056, PROT_NONE) = 0
mmap(0x40032000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0x1a000) = 0x40032000
close(3) = 0
open("/lib/libcrypt.so.1", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0755, st_size=64595, ...}) = 0
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\20\f\0"..., 4096) = 4096
mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40033000
mmap(0, 183036, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x40034000
mprotect(0x40039000, 162556, PROT_NONE) = 0
mmap(0x40039000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0x4000) = 0x40039000
mmap(0x4003a000, 158460, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x4003a000
close(3) = 0
open("/lib/libc.so.6", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0755, st_size=4118299, ...}) = 0
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\250\202"..., 4096) = 4096
mmap(0, 993500, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x40061000
mprotect(0x4014c000, 30940, PROT_NONE) = 0
mmap(0x4014c000, 16384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0xea000) = 0x4014c000
mmap(0x40150000, 14556, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x40150000
close(3) = 0
write(2, "/usr/local/apache/docroot2/cgi-b"..., 40/usr/local/apache/docroot2/cgi-bin/texis) = 40
write(2, ": ", 2: ) = 2
write(2, "/lib/libcrypt.so.1", 18/lib/libcrypt.so.1) = 18
write(2, ": ", 2: ) = 2
write(2, "version `GLIBC_2.0\' not found (r"..., 84version `GLIBC_2.0' not found (required by /usr/local/apache/docroot2/cgi-bin/texis)) = 84
write(2, "\n", 1
) = 1
write(2, "/usr/local/apache/docroot2/cgi-b"..., 40/usr/local/apache/docroot2/cgi-bin/texis) = 40
write(2, ": ", 2: ) = 2
write(2, "/lib/libm.so.6", 14/lib/libm.so.6) = 14
write(2, ": ", 2: ) = 2
write(2, "version `GLIBC_2.1\' not found (r"..., 84version `GLIBC_2.1' not found (required by /usr/local/apache/docroot2/cgi-bin/texis)) = 84
write(2, "\n", 1
) = 1
write(2, "/usr/local/apache/docroot2/cgi-b"..., 40/usr/local/apache/docroot2/cgi-bin/texis) = 40
write(2, ": ", 2: ) = 2
write(2, "/lib/libm.so.6", 14/lib/libm.so.6) = 14
write(2, ": ", 2: ) = 2
write(2, "version `GLIBC_2.0\' not found (r"..., 84version `GLIBC_2.0' not found (required by /usr/local/apache/docroot2/cgi-bin/texis)) = 84
write(2, "\n", 1
) = 1
write(2, "/usr/local/apache/docroot2/cgi-b"..., 40/usr/local/apache/docroot2/cgi-bin/texis) = 40
write(2, ": ", 2: ) = 2
write(2, "/lib/libc.so.6", 14/lib/libc.so.6) = 14
write(2, ": ", 2: ) = 2
write(2, "version `GLIBC_2.1\' not found (r"..., 84version `GLIBC_2.1' not found (required by /usr/local/apache/docroot2/cgi-bin/texis)) = 84
write(2, "\n", 1
) = 1
write(2, "/usr/local/apache/docroot2/cgi-b"..., 40/usr/local/apache/docroot2/cgi-bin/texis) = 40
write(2, ": ", 2: ) = 2
write(2, "/lib/libc.so.6", 14/lib/libc.so.6) = 14
write(2, ": ", 2: ) = 2
write(2, "version `GLIBC_2.0\' not found (r"..., 84version `GLIBC_2.0' not found (required by /usr/local/apache/docroot2/cgi-bin/texis)) = 84
write(2, "\n", 1
) = 1
_exit(1) = ?