Sorry…I had the same problem last night and finally decided my multiple blog strategy would be better using the standard WP product and swapping table prefixes.
I found this same question asked several times in search, but never answered.
My assumption had been that the problem was due to lack of permission for either the smartycache folder – when I installed the script changed the owner on that folder to www…
Best of luck. BTW, I posted exactly this question last night – did it get moderated/deleted?