given your post I decided to try embedding into variable $query and then calling prepare, thanks to the thezip I also turned on logging for dbi and have a tracefile, here is what I have so far, now it appears to execute but I don't get any results to stdout..

###   Rewrite of reminder
###   added dbi & dbd::odbc modules for debugging
###   added data:dumper also for debugging
###   added tracelevel and trace.txt for debugging

use OLE;
use DBI;
use DBD::ODBC;
    use Mail::Sender;
my $trace_level=1;
my $trace_file='tracefile.txt';
DBI->trace($trace_level,$trace_file);

#### lnitialization of Global Variables & Arrays ####
    my $debug =0;
    my $t = time;
    (my $sec, my $min, my $hour, my $mday, my $mon, my $year, my $wday
+, my $yday, my $isdst)=localtime($t);
    $year = $year + "1900";
    my $SQLServer = "servername";
    my $DB = "dbname";
    my $SQLUname = "username";
    my $SQLpass="userpass";
       
    my $query="SELECT ClassSchedule.EventDate AS EventDate, 
                DATEDIFF(dd, { fn NOW() }, ClassSchedule.EventDate) AS
+ Until, 
                DATEDIFF(dd, ClassRoster.Enrolled, ClassSchedule.Event
+Date) AS Since, 
                Classes.Duration AS Duration, 
                Classes.Topic AS Topic, 
                Classes.Description AS Description, 
                ClassLocation.Location AS Location, 
                ClassLocation.Address AS Address, 
                ClassLocation.Directions AS Directions, 
                ClassLocation.Map AS Map, 
                ClassRoster.idEnrollee AS idEnrollee,
                ClassRoster.System AS System,
                ClassRoster.Account AS Account,
                ClassRoster.PublicID AS PublicID,
                ClassRoster.Name AS Name,
                ClassRoster.Email AS emailAddress
            FROM ClassSchedule 
                INNER JOIN
                    Classes ON ClassSchedule.id_Class = Classes.idClas
+s 
                INNER JOIN
                    ClassRoster ON ClassSchedule.idEvent = ClassRoster
+.id_Event
                INNER JOIN
                    ClassLocation ON ClassSchedule.id_Location = Class
+Location.idLocation
                WHERE (ClassSchedule.EventDate > { fn NOW() }) AND 
                    (ClassRoster.Cancelled IS NULL) AND 
                    (ClassRoster.Reminded IS NULL) AND 
                    (DATEDIFF(dd, ClassRoster.Enrolled, ClassSchedule.
+EventDate) > 7) AND 
                    (NOT (DATEPART(dw, { fn NOW() }) IN (1, 7))) AND 
                    (DATEDIFF(dd, { fn NOW() }, ClassSchedule.EventDat
+e) < 7)";

    # Connect to the database
# See footnote 1

my $dbh = DBI->connect("dbi:ODBC:driver=SQL Server;Server=VASVCSSQL;da
+tabase=MLXhelp;uid=$SQLUname;pwd=$SQLpass;") or die  "Couldn't open d
+atabase: $DBI::errstr; stopped";
print "connected finally";

# Prepare the SQL query for execution
my $sth=$dbh->prepare($query);
$sth->execute() or die "Couldn't execute statement: $DBI::errstr; stop
+ped";

$sth->finish();


$dbh->disconnect();
[download]

finally tracefile.txt...

 DBI 1.48-ithread default trace level set to 0x0/1 (pid 5748)
    -> DBI->connect(dbi:ODBC:driver=SQL Server;Server=VASVCSSQL;databa
+se=MLXhelp;uid=Frank;pwd=fu3go;, , ****)
    -> DBI->install_driver(ODBC) for MSWin32 perl=5.006001 pid=5748 ru
+id=0 euid=0
       install_driver: DBD::ODBC version 1.13 loaded from C:/Perl/site
+/lib/DBD/ODBC.pm
    <- install_driver= DBI::dr=HASH(0x2b1bf3c)
    <- default_user(undef undef ...)= ( undef undef ) [2 items] at DBI
+.pm line 580
    <- connect('driver=SQL Server;Server=servername;database=dbname;ui
+d=username;pwd=userpass;' undef ...)= DBI::db=HASH(0x2e8b33c) at DBI.
+pm line 598
    <- STORE('PrintError' 1)= 1 at DBI.pm line 645
    <- STORE('AutoCommit' 1)= 1 at DBI.pm line 645
    <- STORE('Username' undef)= 1 at DBI.pm line 648
    <> FETCH('Username')= undef ('Username' from cache) at DBI.pm line
+ 648
    <- connect= DBI::db=HASH(0x2e8b33c)
    <- STORE('dbi_connect_closure' CODE(0x2e8b294))= 1 at DBI.pm line 
+668
    <- prepare('SELECT ClassSchedule.EventDate AS EventDate, 
                DATEDIFF(dd, { fn NOW() }, ClassSchedule.EventDate) AS
+ Until, 
                DATEDIFF(dd, ClassRoster.Enrolled, ClassSchedule.Event
+Date) AS Since, 
                Classes.Duration AS Duration, 
                Classes.Topic AS Topic, 
                Classes.Description AS Description, 
                ClassLocation.Location AS Location, 
                ClassLocation.Address AS Address, 
                ClassLocation.Dire...')= DBI::st=HASH(0x2e8b9d4) at te
+st2.pl line 61
dbd_describe failed, dbd_st_execute #2...!
    <- execute= -1 at test2.pl line 62
    <- finish= 1 at test2.pl line 64
    <- disconnect= 1 at test2.pl line 67
    <- DESTROY(DBI::st=HASH(02E8B9D4))= undef
    <- DESTROY(DBI::db=HASH(02E8B33C))= undef
    <- disconnect_all= '' at DBI.pm line 677
!   <- DESTROY(DBI::dr=HASH(02B1BF3C))= undef during global destructio
+n
[download]