What would have been the problem? Today March 28, 2015 as President Goodluck Jonathan experienced some sort of dilemma when he arrived at his polling unit, when it reportedly took over 30 minutes to get him accredited ahead of the Presidential elections.

Jonathan arrived with his wife, Patience at Unit 13, Ward 39 in Otuoke, Bayelsa State at about 9:17AM to get accredited but faced a delay in the process.
The President patiently stood for over 30 minutes as the card reader malfunctioned. Three card readers failed to work, a fourth was produced and began working. 
He left the polling unit with his wife and later returned to get accredited.
INEC officials arrived at 8:30AM - until Jonathan arrived, Channels TV reports that no one was accredited before then.
"I want to use the opportunity to congratulate Nigerians as we vote in a president.  There may be issues, because this is the first time we are using this technology,” Jonathan said told reporters on ground.
"I had issues but it’s been sorted, I can't be a ghost voter (laughs), I'm not worried. There may be a delay but I encourage Nigerians to conduct a credible and peaceful elections. If I can endure, I plead with all Nigerians,”  he added.
President Jonathan also said that he had spoken with the INEC Chairman, Attahiru Jega to find out how the polls were going across the country.

Fun Fact:
Here's what you need to know, about this accreditation process if you were out there today voting I'm sure you'll see that the same thing happened to about 45% of the crowd that came out to vote. The device couldn't complete most accreditation.  
This new card reading system was just introduced and we expect to have a little challenge. I'm sure by the next time it'll be a whole lot easier.