I'm wondering someone might have encountered this and figured out a workaround.
When I installed a CMS site using the same database settings and credentials, it installs just fine.
But when I install Commerce with the same settings and credentials, this is what I get whether I specify a license or not.
"===in trapping ex ===An unhandled error has occured:The ConnectionString property has not been initialized.When executingAt C:\Program Files (x86)\EPiServer\CMS\6.1.379.0\Install\Modules\EPiServer Commerce 22.214.171.124\Install EPiServer Commerce.ps1:298 char:21+ $sqlConnection.Open <<<< ();inTransaction = TrueAn error has occured and the transaction will be rolled backRolledbackDeleting Commerce Manager site folder C:\EPiServer\Sites\SampleCommerceManagerDeleting Commerce Manager ExternalFiles C:\EPiServer\eCommerceFramework\5.2\SampleCommerceManagerDeleting Commerce Manager database dbEPiServerCommerceManagerStarted a transacted installThe database dbEPiServerCommerceManager was not deleted because it did not existEntering commit phaseCommittedAt C:\Program Files (x86)\EPiServer\CMS\6.1.379.0\Install\Modules\EPiServer Commerce 126.96.36.199\Install EPiServer Commerce.ps1:298 char:21+ $sqlConnection.Open <<<< ();System.Management.Automation.ParentContainsErrorRecordException: Exception calling "Open" with "0" argument(s): "The ConnectionString property has not been initialized."
I hope someone can help me with this.
I also had some trouble with the Commerce installation. Here's a blog post I wrote about it. Hope it helps you.
Note this is for Commerce 1.0. I have not tested if Commerce 1.1 is different.