I use onclick javascript to use with Conga Composer instead of URL to check validations. But I do get 'The id parameter is missing' error when running the code. It looks like the url does not get the ID.
{!REQUIRESCRIPT("/soap/ajax/29.0/connection.js")}
if('{!Enrolment_Request__c.Validation_Failed__c}' == true)
{
alert('Please check values in all required fields.');
}else{
window.location.href = '/apex/APXTConga4__Conga_Composer?SolMgr=1?id={!Enrolment_Request__c.Id}';
serverUrl="{!API.Partner_Server_URL_370}";
Id="{!Enrolment_Request__c.Id}";
QueryId="[GetContactDataforETA]a2B0M000000HP1n";
TemplateId="a2J0M000000J9D4";
DS7="1141";
CSVisible="1141";
CSRoutingType="SERIAL";
CSRecipient1="{!Enrolment_Request__c.Workplace_SignatoryId__c}";
CSRecipient2="{!Enrolment_Request__c.LSA_SignatoryId__c}";
CSRecipient3="{!Enrolment_Request__c.Trainee_SignatoryId__c}";
FlattenPDFForms="1";
}