503 (Service Unavailable) - IIS 7.5 deployed MVC web application - asp.net-mvc

Question

Every 24 hours or so, we receive a 503 from our IIS 7.5 web server that hosts our MVC application.
I read some related articles and checked if the Application Pool/Identity had the necessary permissions and was a part of the IIS_USR (or whatever it is called) group.
The event log reports that the ASP.NET worker process crashed. This is the information from the event log:
Log Name: Application
Source: Application Error
Date: 5/14/2013 11:15:58 PM
Event ID: 1000
Task Category: (100)
Level: Error
Keywords: Classic
User: N/A
Computer: SERVER_MACHINE_NAME
Description:
Faulting application name: w3wp.exe, version: 7.5.7601.17514, time stamp: 0x4ce7a5f8
Faulting module name: unknown, version: 0.0.0.0, time stamp: 0x00000000
Exception code: 0x00000000
Fault offset: 0x1ccbc2de
Faulting process id: 0x2640
Faulting application start time: 0x01ce51338e238a4b
Faulting application path: C:\Windows\SysWOW64\inetsrv\w3wp.exe
Faulting module path: unknown
Report Id: e8120b0c-bd26-11e2-9313-001f290b5f7a
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Application Error" />
<EventID Qualifiers="0">1000</EventID>
<Level>2</Level>
<Task>100</Task>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2013-05-15T06:15:58.000000000Z" />
<EventRecordID>4265</EventRecordID>
<Channel>Application</Channel>
<Computer>SERVER_MACHINE_NAME</Computer>
<Security />
</System>
<EventData>
<Data>w3wp.exe</Data>
<Data>7.5.7601.17514</Data>
<Data>4ce7a5f8</Data>
<Data>unknown</Data>
<Data>0.0.0.0</Data>
<Data>00000000</Data>
<Data>00000000</Data>
<Data>1ccbc2de</Data>
<Data>2640</Data>
<Data>01ce51338e238a4b</Data>
<Data>C:\Windows\SysWOW64\inetsrv\w3wp.exe</Data>
<Data>unknown</Data>
<Data>e8120b0c-bd26-11e2-9313-001f290b5f7a</Data>
</EventData>
</Event>
Deployment Environment:
Web Server: IIS 7.5
.NET Framework: v4
MVC version: 4
Windows Server: Windows Server 2008 R2 Standard
Help appreicated.