Jhakataka and bhakataka?

[Martin Gansten]

Many thanks to Madhav, Patrick and Christophe for providing additional 
sources for the quotation 'vidyā ha vai ...'. I now have a rather 
different question:

In a late 16th-century text (the Praśnatantra attributed to Nīlakaṇṭha) 
I came across the two words jhakaṭaka and bhakaṭaka, which I have been 
unable to find in any dictionary. A Google search tells me that the 
former occurs in Samantabhadra's Ratnakaraṇḍaśrāvakācāra, but brings me 
no closer to a meaning. Any light on these two words would be most 
appreciated.

Martin