DISM fails after SQL Silent install

I am working with an Installscript Project and i have a few features that the user can install. When the user selects to install both SQL Server Express 2008 and a webclient application, DISM is failing.

SQL install runs first and installs with no issues, the Webclient installs second and first uses DISM to enable my required IIS components. The problem is that it seems like the SQL install has something open that is causing the DISM app to fail. I look in the log file and i see multiple lines stating "DISM Manager: PID=4000 Failed to create the image session process. A process is already servicing the image. - CDISMManager::CreateImageSession(hr:0x800700b7)"

If i omit installing the SQL server then the DISM tool works as it should with no issues at all. I have not been able so far to figure out what is causing the failure with SQL..

Is this a pure InstallScript project or a InstallScript MSI project? The behavior you report sounds suspiciously like the latter, where running SQL Server Express 2008 R2 will drop the MSI handle after it performs its own checks for supported operating system. I cannot say for sure though if this is the issue you are encountering. Another thing I would try myself is enabling the UI for the install of SQL Server 2008 by removing the /Q parameter and see if the install is somehow reporting that it is complete too soon. What do the logs from SQL Server report?