Salesforce Error : Callout from scheduled Apex not supported.

Hi ,

I am using apex code to send a report as an attachment and schedule it but in Scheduling i am getting this error
"Scheduler: failed to execute scheduled job: jobId: 7012D00000IDppK, class: common.apex.async.AsyncApexJobObject, reason: Callout from scheduled Apex not supported."
here is my code:
global class Exporter implements System.Schedulable {
global void execute(SchedulableContext sc) {
ApexPages.PageReference report = new ApexPages.PageReference('/00O41000001kkjC?csv=1');
Messaging.EmailFileAttachment attachment = new Messaging.EmailFileAttachment();
attachment.setFileName('scheduledreport.csv');
attachment.setBody(report.getContent());
attachment.setContentType('text/csv');
Messaging.SingleEmailMessage message = new Messaging.SingleEmailMessage();
message.setFileAttachments(new Messaging.EmailFileAttachment[] { attachment } );
message.setSubject(' Test Client list Report');
message.setPlainTextBody('The report is attached.PFA');
message.setToAddresses( new String[] { 'cromahead@gmail.com' } );
Messaging.sendEmail( new Messaging.SingleEmailMessage[] { message } );

}
}
Now i am not getting that where i am using Callout  services. How to resolve this?

Thanks in advance!

Rahul Kumar