Question : Problem: DPM 2007 Fails to backup exchange 2007 store

We are running a single Exchange 2007 server and just replaced backup exec 11d with DPM 2007.  I am using the Microsoft recommended "Firestreamer" product to allow quasi tape backups to local disk.  Backups are currently failing with error details: "Failed to perform the operation since the free tape is not available in Stand Alone Drive Tape Library Firestreamer Drive - ID 24050"  

Having said that, I am using the same backup destination for file server backups through DPM and those jobs complete perfectly.  Space is not an issue as the current firestreamer 'image' is hovering right around 14 GB on a drive with 300GB + of capacity.  Not sure why this is only happening with exchange jobs?  

Answer : Problem: DPM 2007 Fails to backup exchange 2007 store

Install DPM FeaturePack 1 to enable colocation of different Protection Groups on the same streamer. (even virtual)

FeaturePack 1 x64
http://www.microsoft.com/downloads/details.aspx?FamilyID=ad5cd1a2-9b87-4a2c-90a2-9dbaf1024310&DisplayLang=en

FeaturePack1 x32
http://www.microsoft.com/downloads/details.aspx?FamilyID=ad5cd1a2-9b87-4a2c-90a2-9dbaf1024310&DisplayLang=en

After update. (from DPM Blog)
Enabling/Disabling co-location of data on Tape With DPM 2007 Feature Pack (KB949779), we have added support for media co-location. With this feature, you can achieve better tape utilization by co-locating data from multiple protection groups with similar retention range. This feature is disabled by default. You can use following PowerShell commands to enable and disable tape co-location.
Enable Tape co-location:
Set-DPMGlobalProperty -DpmServer -OptimizeTapeUsage $true
Disable Tape co-location:
Set-DPMGlobalProperty -DpmServer -OptimizeTapeUsage $false
You can verify the status of tape co-location feature (Enabled/Disabled) from Library Management tab of DPMUI.