>Is there a way to check if a table is openmed exclusively?

In addition to Sergey's reply. If you want to check, if file is opened exclusive from another computer, you may just try to open it with low-level functions and close, e.g.

local lnHandle
lnHandle=fopen("yourfilewith fullpath")
if m.lnHandle>0 and fclose(m.lnHandle)
   * File is not opened exclusive
else
   * file is opened exclusive
endif

Or you can try to use it, but trap for possible errors.