If you use a combination of CreateProcess and WaitForSingleObject, you can be assured that each task will finish before another starts. Here's a good article on the subject:
http://support.microsoft.com/default.aspx?scid=kb;EN-US;q191584 - HOWTO:
Determine When a 32-bit Process has Completed from VFP

>After a user types a drawing number in a text box the following needs to take place:
>Verify the Drawing Revision(SPT to AS400 database)
>
>Find the Drawing in the proper release folder
>
>Copy Drawing Files to Temporary Folder
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>Run a batch file that takes each Drawing file Opens it up in it's native application and then through script plots the Drawing out to a postscript file.
>
>Automate Acrobat Distiller to take the .ps files and make them .pdf files.
>
>Erase .bak, .ps, and .log Files
>
>Automate Acrobat to take all the pdf files and make them one pdf file.
>
>I can get all these pieces to work when involked one at a time. How do I get these steps to work in a liner fashion without overrunnig each other.