You can ask the author of the script which tcl http package does the script require.
Btw the egghttp.tcl is the original one, because the site where you have downloaded it from (if it is
www.tclscript.com) the author's scripting website who has coded this http script himself. (So it ought to be updated as it's the authors website!) And same goes for bgexec.tcl!
To my knowledge egghttp.tcl and bgexec.tcl are the main and one and only widely used scripplets for this purpose, coded by strikelight. I haven't seen any other though.
Plus it has the highest number of downloads on his site, meaning its the most widely and commonly used one by almost everyone/everyscript. Maybe it doesn't work with your tcl so you might ask the author of that script which does he recommend to use.