creating opportunity returns error

What steps will reproduce the problem?
1. Creating opportunity from a contact related list, for a certain contact 
(meaning it consistently fails for one contact and works for another one) 
returns the following error: 

2. see also case #05078806
3.

What is the expected output? What do you see instead?
Unable to Access Page 
Invalid parameter value "321321545" for parameter "conid". 

Error: The value of the parameter specified above contains a character that is 
not allowed or the value exceeds the maximum allowed length. Remove the 
character from the parameter value or reduce the value length and re-submit. If 
the error still persists, please report it to our Customer Support team and 
provide the URL of the page you were requesting as well as any other related 
information 

URL: 

https://eu1.salesforce.com/006/e?lookupcmpgn=1&retURL=%2F321321545&accid=001D000
000g72cF&conid=321321545&RecordType=012D0000000FTxG&ent=Opportunity&opp3=%D7%9E%
D7%A9%D7%94+%D7%96%D7%95%D7%9B%D7%9E%D7%99%D7%A8-+Donation+30%2F03%2F2011 

What version of the packages are you using?
2.0/9

Please provide any additional information below.
I initially thought it was the Hebrew local language.
However, it works for some contacts and fails for others!
Support login is granted and you may change language settings at will.

Thanks,
Gal

Original issue reported on code.google.com by galavr2...@gmail.com on 2 Apr 2011 at 7:23

sfdc-SupportDevelopment / npsp

creating opportunity returns error #247