The Welsh Assembly's audit committee pinpointed the rush to set up Education and Learning Wales as a key cause of excessive costs of more than pound;2 million.
It says this mis-spending happened when the four Welsh private-sector training and enterprise councils were swallowed up by Elwa. Many of their staff had not been instructed in the stricter contract-awarding and book-keeping procedures which would come into force.
The change-over occurred on March 31, 2001, with minimal preparation, auditors have found. Five offices across Wales came into operation the following morning, each working to different procedures and financial rules, auditor General Sir John Bourn found.
A Civil Service College training programme has been in action only since last July - with training not having begun until January.
The Welsh cabinet has accepted the criticisms only "in part", and says its officials were aware of the risks.
Its statement said: "The Government considers adequate time was available for the setting up of the National Council for Training and Education in Wales (which forms part of Elwa) and at no stage in the process did those involved say that this was not achievable.
"It does not accept the conclusion that insufficient attention was paid by its officials to the risks inherent in the reorganisation."
Despite its claim that officials were paying "attention", the Cabinet admits that the Welsh Assembly's top officials - including permanent secretary Sir Jon Shortridge - had not been aware of the Cabinet Office publication Non-departmental public bodies: a guide for departments.
It was this document, widely regarded as essential reading, which audit chairman and former MP Dafydd Wigley had dramatically produced during his cross-examination of officials.
All staff with even the remotest link with quangos have now been sent copies.