Despite of 2 service packs and the numerous hotfixes we installed since the release of Sql Server 2005, we still discover problems with SSIS much too often. This time, it was some weird message in our acceptance environment telling me the "Script files failed to load". I had thoroughly tested the package on our development environment, so I was amazed to hear it failed on another environment.
A quick search on the specialized forums returned some hits - mostly related to the Script task the package contained - but nothing really described the conditions I faced. The only difference I could think of was the fact that the acceptance environment was a 64-bit edition, unlike development. In such a case, the settings of the Script task are quite simple: the PrecompileScriptIntoBinaryCode flag should be on.
There was a non-active breakpoint however that caught my attention which I hadn't noticed before because the Script task was not part of my changes to the package and the tests had never halted at that break. After removing the breakpoint, the package effectively ran without a problem.
It's a shame we had to discover this bug the hard way, but it proves that an acceptance environment should stick as close to production as possible. In this case, it payed off.