SSIS Connection Error - File name not valid - sql-server-2005

Question

I'm seeing an issue with an SSIS (SQL Server 2005) job where I'm getting the following error:
The file name "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=\UNC\FOLDERS\filename.xls;Extended Properties="EXCEL 8.0;HDR=YES";" specified in the connection was not valid.
My searching around this site and others indicates that the most common cause of this is a permissions error but I don't believe that's the case in this situation since any number of files have successfully been processed through this implementation.
Here's an overview of the setup:
Vendors FTP files to us on a daily basis that a Windows service picks up, copies to a temporary directory and then calls SSIS jobs on those files. There are two SSIS jobs for each vendor one for a snapshot data feed and one for a transaction listing.
There are currently over 50 different SSIS jobs in the overall process. All of them work except for one specific transaction job which fails with the above error in a script task step. Files come in at least daily with unique file names so I grab the job, determine the vendor based off the source directory and then the file type based off indicators in the file name to determine which SSIS job to call. Since file names change every day, when the service calls the SSIS job, I pass in a series of parameters including the vendor file name so it can properly connect to the file.
Each job begins with a script task that sets necessary variable values for the rest of the job. For example, since the vendor file name changes with each run, I pass in the vendor file name through the SSIS variables collection then set the connection string of a datasource using that file name as the DataSource in the string. It is at that point of the script task that the above error occurs. Here's the task script code where the error occurs:
Dts.Connections("Transactions File").ConnectionString = _
Dts.Variables("ConnectionString").Value.ToString().Replace("##FILE_PATH##", sourceFilePath)
The ConnectionString value is: Provider=Microsoft.Jet.OLEDB.4.0;Data Source=##FILE_PATH##;Extended Properties="EXCEL 8.0;HDR=YES";
The sourceFilePath is the full UNC path to the vendor file in the processing directory
I don't believe it's a permissions error since all the other files going through this process (using the same holding directory for processing) are working. It shouldn't be an issue of the file not existing since again it follows the same process as every other file and I have verified the file properly ends up in the correct directory. I also considered that the connection string might be too long, but the filepath ends up at 109 characters and even with a shorter (<90) full path, the same error occurs.
Is there anything else you can you think of for me to look at? Thanks for any help.

Answer 1

Based on the information presented, you are doing everything correct. If you're new to SSIS, one thing I'd suggest, is that you get a copy of the excellent add-in BIDSHelper. It has great features that can really save you time especially with regard to configurations and expressions.
I created a reference package that had an Excel Connection Manager pointing to C:\ssisdata\so_paulsmithjr.xls and wired everything up.
At this point, I know things are working so it was time to make the package move. I created the following variables and their values
CurrentFile - C:\ssisdata\so_paulsmithjr.xls
PlaceHolder - ##FILE_PATH##
TemplateConnection - Provider=Microsoft.Jet.OLEDB.4.0;Data Source=##FILE_PATH##;Extended Properties="Excel 8.0;HDR=YES";
A fourth variable is set to be an expression (Right click on variable, properties window. Set Evaluate as Expression = True & Expression is below)
CurrentConnection - REPLACE(#[User::TemplateConnection], #[User::PlaceHolder], #[User::CurrentFile])
I compared the CurrentConnection value to the ReferenceConnection (which is the original value of the Excel Connection Manager's connection string) and things were a match. At this point, if I were to change the value of CurrentFile to C:\ssisdata\so_paulsmithjr - Copy.xls, that would automatically be reflected in the value of CurrentConnection.
The final trick would be to use an Expression on the Excel Connection Manager. Again, right click on the CM and under Properties, there will be Expressions. It won't expand as there is nothing under it. Instead click the ellipses and then select ConnectionString property and select the ellipses again and this time drag down the #[User::CurrentFile] variable. Click OK x2 and now your connection manager is set to use wherever the CurrentConnection variable specifies.
Does that work any better?