With 10.50.1702.0 RTM Data Center Edition (64-bit) and Report Builder 3, I'm getting the following error when I attempt to execute a report: The attempt to connect to the report server failed. Check your connection information and that the report server is a compatible version. There is an error in XML document (1, 4093). '.', hexadecimal value 0x00, is an invalid character. Line 1, position 4093. I see many many references to this error in these forums. But the answers there seemed garbled or not useful.... http://social.msdn.microsoft.com/Forums/en/sqlreportingservices/thread/a6b37758-5ced-4caa-8823-42f31fca0a96 http://social.msdn.microsoft.com/Forums/en/sqlreportingservices/thread/99a62d7e-5df3-43aa-8273-0a2bf418fbd3 http://social.msdn.microsoft.com/Forums/en-US/vsreportcontrols/thread/633cae79-665d-42a4-9c18-160bd69f2ddc I've checked the report rdl file in question... 1) line 1 isn't that long. It's simply the xml directive. 2) If I go to the stream offset 4093 there's nothing interesting there. 3) If I upload the repot via RB3 or simply use the website to upload the report I get the same error or similar error (offset different) when I attempt to execute it. 4) I've scanned the file for illegal characters and came up with nothing. In particular there are no nulls in the file. 5) I loaded the cumulative update package #1 since there was a similar error KB 977889. But the error still occurs. Resetting the app pool didn't help. I have a couple of observations to the problem: A) Perhaps data is being pulled in from a query in the report that might have NULL's. I have no idea the transformations the rdl file goes thru as it becomes a report. B) It doesn't seem particularly a RB3 issue since, since I'm uploading via the Reporting Services website on my server. It looks like the code that uploads the report is broken. My Reporting Services installation is a boat anchor with this error. Any ideas?

Ah! So my first supposition A) was correct. We had a table with column of containing computer processed values that contained control characters (our bug), being put into a dropdown on the report. I created a scalar valued function to filter the column to toss the control characters and all was well! Clearly SSRS is creating a new XML file for use internally with the injected param data and then barfing with a very weak error message as it parses it later. A good error message would have saved me 2 days of research!