Excessive compile blocking on sp_procedure_params_90_rowset
There is an excellent blog post 
http://blogs.msdn.com/b/support_sql_france/archive/2012/02/07/sql-server-compilation-gateways-and-resource-semaphore-query-compile.aspx
that explains what's happening.  

SQL Server allows for a set number of compilations based on their complexity.  It groups them into small, medium, and large.  For large compilations, there can be onlyi one compiled at a time, so let's say all of your procs are considered large, then each one has to be compiled serially.  That could account for the blocking.
I think there may be several approaches to the problem - consider more resources (more CPUs will allow more small and medium queries to be concurrent or may up the threshold for what is considered medium).  Also, more memory may solve the problem.

If you're like most of us, that might not be possible.  Another option might be to review the ADO calls and see if the number of calls can be reduced or spread out so that not all calls happen at the same time.  Reducing the number at any given time should reduce your wait time.

If that doesn't work, consider fixing the 'compilability' of the stored procs.  Maybe break them down into smaller chunks which might reduce them to the small or medium buckets and allow more parallel compilations.  Or determine why the procs need to be recompiled each time.  See if they can be rewritten such that they don't need to be recompiled.  Finally, I'd consider using Plan Guides.  These will allow the procs to be precompiled and may save some time.

Hope that helps