Memory writes from separate execution thread

We have developed a set of scripts such that we source one on the Palladium and it waits for command files to be present, then from a remote machine we can copy a command file over to the server and have our commands executed. In the sourced script, I have something like the following:

after 1000 check_command_files
vwait stop

and inside the check_command_files proc, I look for certain files and then source that file.

The sourced file might contain other "source" lines.

The problem I am running into is that writing to memory areas from those secondary sourced files. When I try and source them, the memory writes are not completing correctly, I get an error that it could not complete.

Is there an issue with multiple sourcing like that? Is there anything I need to do in my TCL scripts to make the variables from higher level sourced scripts available? Is there something I need to do special to write to memory regions from those sourced scripts?

Thanks

Alex