I have completed a report and I am recieivng an error that I cannot get rid of or bypass.  Is there a work around?  I created and deleted the report on 5 different occassions.  The system will not allow me to create the report, with the (Cases by Status name), This error is holding up progress.  Are there any suggestions?  I can't choose a different name, becuase the module is looking for the above name.

Validation Errors While Saving Record(s)
There were custom validation error(s) encountered while saving the affected record(s). The first validation error encountered was "This Report Unique Name already exists or has been previously used. Please choose a different name.". 

I am receiving the below error.

Challenge Not yet complete... here's what's wrong: 
Please check that you have a filter for Stages that are not equal to Closed Won or Closed Lost.

I have the below screen shot as my input.  I am baffled at what is incorrect.  I created the filters under Opportunities, with the below criteria.  Am I missing subfilters or is my initial inpit that would cause the error.

 
From
To 
Amount greater than ""25,000""
EditRemove
AND
Stage not equal to "Closed Won"
EditRemove
AND
Stage not equal to "Closed Lost
 

In the  Report and Dashbaord trial, I am having issues generating a report.  On the Open the menu on the Total Cost column and select Summarize this Field.... I have (0) files showing.  Is this an issue with previious models, in regards to me not having any data present,  I ahev tried all of the steps on multiple occassions and I get the same results.

Please advise if I have missed any steps or if there are issue with supporting data

The Error I get is: "Step Not yet complete... here's what's wrong: 
Please check that your report includes at least all of these columns: Supply: Supply Name, Unit Cost, Quantity and Total. 
Note: you may run into errors if you've skipped previous steps."
this is my report:

not sure where I made a mistake

Just downloaded an app to my sandbox from the appexchange for the first time.  I am then prompted to sign into the sandbox but my SFDC credentials do not allow me in.  How do I get access to a Sandbox?