I cannot refresh all of the queries in my spreadsheet
 

I have a spreadsheet which has 20 worksheets in it and each sheet contains
around 10 queries from an Access database. However, when I use the 'Refresh
All' funtion I get the following error message "[Microsoft][ODBC Microsoft
Access Driver]Cannot open any more databases".

I created a macro which refresh the queries on one worksheet at a time, but
after the running the macro on the forth the sheet the same error message
appeared.

Does anyone know how I can refresh the queries in my spreadsheet or have I
simply exeeded the number of Access queries that an Excel worksheet can
handle?